Filed under: Bars
December 13, 2022

Caramel S’mores Bars aka OMG Bars 

Vanilla bean marshmallow laced with dark chocolate, a layer of salted caramel on the bottom all held upright by a graham cracker crust. 

4.82 from 22 votes
Yield: 16 bars
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Recipe overview 

These are inspired by a sweet from my favorite cupcakery in DC, Baked & Wired. Though I’m usually there for the carrot cake concoction, my husband likes to grab anything he spies with marshmallow. So it happens we came home with something they called an OMG Bar one day, and it fascinated me. I couldn’t get it out of my head. You know I love my layers! 


Theirs begin with a layer of graham crust, then caramel, then a marshmallow topped with chocolate ganache. I used my own recipes to create the layers as they are in the original but I had trouble getting the ganache to stay put on the marshmallow (it was doing this sliding thing). So instead, I opted to swirl in some dark chocolate like I do in my brown sugar marshmallows. 


The result is a bar that’s mostly marshmallow; a special brown sugar vanilla bean one at that, interrupted by layered swirls of dark chocolate, a bit of homemade salted caramel on the bottom all on a basic graham cracker crust. It’s sweet and salty with different textures and flavors, so fun to eat! 


How to make Caramel S’mores Bars 


Graham Cracker Crust: You’ll grind the crackers then mix them with melted butter and press into the bottom of a pan. I bake my crusts so they are firm to slice without crumbling, but just for 10 minutes. Simple! 


Caramel: I’m using my basic caramel recipe but modifying it just slightly so it will be firm enough to hold up as a layer. We’re using the dry caramel method, so cooking the sugar until it’s melted then begins to caramelize. Once it’s amber colored, add the heavy cream (careful it will bubble up!) then the rest of the ingredients. While it’s warm and loose, you’ll pour it onto the graham cracker layer and then let it firm up.


Chocolate Swirled Marshmallow: Making marshmallows is basically three parts: blooming the gelatin, cooking the sugar, then whipping them together.

You’ll need a thermometer for the sugar; instant, candy or even laser. It’s going to boil until it hits 250 F and once there, pour it into the stand mixer and add the gelatin. Whip until it’s a thick marshmallow fluff.


Homemade caramel for layered bars

Whether it’s on a brownie, layered between graham crackers and marshmallow, you want a caramel that won’t be too stiff to cut but also not too soft that it will run too quickly at room temperature. 


That’s where the balance comes in for this recipe: it’s buttery, well salted and can hold up well under the marshmallow. It has a delightful pull to it (think, mozzarella cheese pull!) and tastes wonderful against the graham crust. 


To control the amount of liquid that goes into this (so that it isn’t overly runny) I use the dry method: cooking sugar until it melts and caramelized without water. I add a few drops of lemon to the caramel to protect it from crystalizing (which can easily happen with the dry method). 


For bars, especially ones that are going to be sweet up and down, I like to cook the caramel to a darker hue which deepens the flavor and helps firm it up. 


Tips & Troubleshooting for homemade caramel 


  • Make sure to warm the heavy cream before adding it to the hot caramel or the caramel will seize. 
  • Add the heavy cream slowly, one tablespoon at a time, stirring as you do. 
  • If the caramel separates after adding the cream and butter, it can be brought back together by whisking vigorously over heat. Adding the vanilla, which causes it to bubble up, will help at this point too. 


Tips & Troubleshooting Homemade Marshmallows 


  • You can either use a clipped candy thermometer to watch the caramel or a laser, which is cleaner but you’ll want to check the sugar frequently less you overcook it. 
  • Whip the marshmallow fluff until it starts to pull from the sides and is thick. If you overwhip it it will be overly stringy and difficult to remove from the bowl. If you underwhip it it’ll be pretty soft in the pan. 10-12 minutes in the mixer is usually enough. 


Caramel S'mores Bars

Graham crackers, smooth & salty caramel and a chocolate swirled marshmallow on top!
Prep Time: 30 minutes
Cook Time: 20 minutes
Chill Time: 2 hours
Yields: 16 bars
4.82 from 22 votes


Graham Layer

  • 1 ½ cups or 190g cups graham cracker crumbs
  • ⅓ cup or 80g butter unsalted

Caramel Layer

  • 1 cup or 200g sugar
  • ¼ cup heavy cream
  • ½ cup or or 113g butter can use salted here reduce fine sea salt to 1/4 tsp
  • 1/2 teaspoons fine sea salt
  • 1 teaspoon pure vanilla extract


  • 2 envelopes or 17g powdered gelatin
  • ⅓ cup or 85g cool water for the gelatin mixture
  • 1 vanilla bean or 2 teaspoons pure vanilla extract
  • ⅓ cup or 88g cup water for the sugar
  • ¼ cup plus 1 tablespoon or 95g g honey
  • 226g or heaped 1 cup brown sugar
  • ¾ tsp fine sea salt
  • 100 g dark chocolate chopped fine


  • Line a greased 8 or 9” square pan with parchment paper on both sides so they overlap. Preheat the oven to 350 F.

Make the graham crumb layer

  • Grind the crackers into crumbs and melt the butter. Combine them until the mixture is like wet sand. If it seems overly dry, add a bit more melted butter.
    Press the mix into the bottom of the pan in an even layer.
  • Bake for 10 minutes then let cool completely before you make the caramel.

Make the caramel

  • In a deep pot, add the sugar. Squeeze a few drops of a lemon over the sugar and use a wooden spoon to stir it until it’s mostly mixed. Turn the heat on to medium.
  • Warm the heavy cream in the microwave, just for about 30 seconds. Have the other ingredients closeby for the caramel when it’s ready.
  • Stir the sugar frequently as it melts and darkens. Once it is all liquid and amber colored, let it cook for another minute (the longer you leave it the deeper the flavor but if left too long, it will turn bitter).
  • Pour the heavy cream in very slowly, stirring as you do. The caramel will bubble up so be careful. Lower the heat, then add the butter and salt and stir until smooth. Take off the heat and add the vanilla, stir to combine. Pour caramel over the graham layer and set aside to firm up.

Make the chocolate marshmallow layer

  • In a small bowl, add the cool water and the vanilla scrapings (or extract). Then add the gelatin and whisk to combine. Set aside.
  • In a deep pot, add the sugar, water, salt, honey and scraped vanilla bean (if you used a bean). Set over medium heat and stir until combined. Clip a thermometer to the pan and let cook until the mix reaches 245-250 F. Pour into the bottom of a stand mixer bowl and remove the vanilla bean. Let cool for just a minute then add the gelatin (it should be one big glob now) and attach the whisk.
  • Whisk on low to start, then work up to medium and let it whip. Meanwhile, heat the slowly chocolate until almost, but not fully melted (I do this in the microwave) and stir until smooth. Let cool slightly.
  • After about 10 minutes of whipping the marshmallow should be thick, shiny fluff. Pour in the cooled, melted chocolate and give it a couple of big, strong strokes so it swirls a bit.
  • (If the caramel has gone very firm and cool, set it in the oven to warm up and loosen a bit so the marshmallow layer will adhere to it better.)
  • Pour the marshmallow over the caramel and gently get it into an even layer.
  • Set the bars aside for about 4 hours to firm up. To slice, warm up a knife under hot water and dry it (a little oil on the knife helps cut through the marshmallow without sticking).
  • Store bars in the fridge if making them ahead of time. These slice best at room temperature.

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Recipe Reviews

  1. 3 stars
    Was really disappointed that my crumb base didn’t stay together and crumbled when cutting leaving a thin layer of crumbs below the caramel. I wish there was more instruction on the caramel as mine didn’t set well enough and was incredibly soft, oozing out below the marshmallow. Good caramel though, just too soft. That leaves the marshmallow that was absolutely delicious and set beautifully. I think the marshmallows were a do-over, but maybe not the rest of it. Or maybe I’ll try folding the caramel in with the chocolate next time? Yummy flavor though.

  2. Made these on New’s Years Day instead of making any resolutions that would keep me from eating them. ???? And they are worth every second I spent on them. Delicious and perfect. Could easily be sold at a fancy bakery.

  3. The caramel is delicious and I love this technique- I have never used the lemon juice (I used lime) and sugar technique. It made a fabulous caramel in no time. The combination of the caramel and graham cracker are good enough to be a dessert on their own. I think I overcooled the marshmallow so it didn’t pour out so beautiful and the chocolate was messy looking but I’ve made this marshmallow recipe on its own before so I know it was user failure. This is a show stopping dessert.

  4. I just finished making these for Christmas Day dessert. I cannot wait to enjoy my hard work lol. Directions were perfection!

  5. 5 stars
    These are very tasty! But, my graham cracker crust totally crumbled apart when I went to slice them. Not sure what went wrong, maybe I didn’t use enough butter? But overall very tasty, especially the chocolate swirled marshmallow!

  6. Can this be made with white chocolate or no chocolate? have a friend who has an allergy to milk and dark chocolate but loves white chocolate.

  7. 5 stars
    THESE ARE SO GOOD! I’ve been wanting to make this recipe forever, but was intimidated (I’ve never made marshmallow before!). I finally just went for it and WOW is it ever delicious. And it’s really not that hard! I just took the time to measure all of the ingredients out before to make sure everything was ready so I didn’t get overwhelmed as I went through, and the steps are super thorough and simple to follow. Thanks Sam for another winner!!

  8. 5 stars
    I just finished getting these in the pan and can’t wait to try them tomorrow for Mother’s Day. I am pretty sure I whipped the marshmallow layer too long…I have made marshmallows before but it was so long ago that I kept second guessing myself. They were pretty difficult to spread, but I got them into a mostly flat layer. I’m guessing this won’t affect the final outcome too much, but now I’m eager to try this recipe again and see if I can get them perfect! 🙂

  9. 5 stars
    These are so yummy! Every recipe I try is a knockout, Sam! I will say, I was short on time so I subbed store bought marshmallows and just drizzled melted chocolate chips overtop of everything. Sorry! But they were excellent, my kids helped, and I’ve already shared the recipe. We will definitely be back again to make the mallows too! The caramel was very straightforward, didn’t seize up, stayed soft and tasted wonderful.

  10. 5 stars
    These are so much better and easier than I thought they would be. There are a couple of first here for me, one of those was to make homemade marshmallows, which I’ve been wanting to do since…. 2005,
    maybe even before then(Alton Brown’s Hey day on Food Network). I’m getting long winded so to sum it up, these are fantastic the recipe is a keeper and I’ll definitely make them again. love ❤️❤️.

  11. 5 stars
    I made these bars to share with friends during the holidays. Everyone loved them and I found them to be delicious. The caramel was so rich and creamy. This was the first time I tried the suggested caramel method. The directions were clear but I felt more comfortable after reading it a few times. I did not experience any issues but I noticed my marshmallow did not adhere to the caramel. It was like the marshmallow was slightly gliding on top of the caramel. This didn’t change the taste, but I am wondering if I should’ve cut larger pieces. I will certainly try them again because they are a wonderfully fun change from traditional holiday desserts.
    Thanks for sharing,

    • Meghan, thank you for the review – glad the caramel worked okay and they tasted good! I truly appreciate your feedback. I think I’ve figured out why the marshmallow isn’t sticking for some, the caramel must be getting a bit too firm before it goes on. I’ve added another step to the instructions that has you warm it up so it’s soft and loose when the marshmallow goes on. This should help it stick! If I find a different method I’ll report back.

  12. 3 stars
    Was really looking forward to these!! Followed the recipe exactly, and my caramel also became rock hard when it set – like the commenter below me. It did not separate from the marshmallow as described below, but we could barely bite in to them, or chew. Any ideas why this might have happened? Thank you!

  13. 5 stars
    Definitely a labor of love, but so worth it!! I do have to say that I had to make the caramel three time before getting it right– it kept seizing up even though I warmed up the heavy cream, but third times a charm I suppose! As for the marshmallow, I was a bit nervous to attempt it, but the instructions were easy to follow and everything went smoothly there! The final product was sooo yummy and as I said, worth all the trials and tribulations! Thank you, Sam?

  14. Hi! Do you think it would work if I mixed blueberry curd into the marshmallow instead of chocolate, subbed the graham cracker crum crust for a shortbread crum crust, and omitted the caramel?

  15. Made these with my husband and although everything individually turned out great (or so we thought) our caramel turned out rock hard! I didn’t see any comments or tips about why this would happen and we were so disappointed!! What would have caused this?? Since the caramel was so hard when we cut into the bars the marshmallow separated from the caramel and so did the Graham cracker crust which just caused a huge mess. How can we avoid this? 🙁

    • Hi Sadah, Im sorry they made a mess =( the caramel shouldn’t have been impossible to cut – it can be rather chewy if you cook it longer than necessary. Did you keep it at room temperature or chilled?

  16. 5 stars
    These are amazing! I love anything almost anything s’mores and these had some small tweaks to the basic s’mores flavors that I really enjoyed. Plus they were fun to make and actually fairly straightforward. The tips in the recipe were helpful too.

  17. Holy wow Sam. This looks complicated so I don’t actually want to make it but I really want someone else to make it and feed it to me because it looks incredible.

    • It does look it but I promise it’s not! The crust is just a press in, then there’s caramel (which ok, is annoying at times but doable) and then a marshmallow (boiling & whipping). It is a project for sure but I feel like a baker with some experience could do it well.