Filed under: Cookies / Drop Cookies
January 19, 2024

Oat Flour Peanut Butter Cookies

Chewy, crinkle peanut butter cookies gluten free and made with oat flour!

5 from 8 votes
Yield: 14 large cookies
Jump to recipe
Oat Flour Peanut Butter Cookies

These started with this small batch peanut butter cookie recipe, but since we are making a full batch I used the whole egg rather than just the yolk. And since making these thick and chunky peanut butter cookies, I’ve been rather drawn to using chunky peanut butter for those added specks of crunchy nuts. Lastly, of course, we’re making these with oat flour instead of all purpose. 


The reason for this is well, I just love oat flour in cookies, brownies, muffins and blondies. But especially in cookies because unlike other ‘alternative’ flours, oat flour behaves quite similarly to all purpose yet it adds a lovely oaty flavor and it makes the cookies extra chewy. This chewiness is what I just adore here. 

These bake up into these gorgeous cracked cookies with crinkles all over, kind of like a molasses cookie look, but with the dual flavor of hearty oats and salty peanut butter. 


Recipe Ingredients 

Butter: Where I usually say you can use salted or unsalted, here I have a preference for unsalted because we’re already getting added salt from the peanut butter. That said, if salted is all you have and you have a ‘saltier’ tooth, you can use it but omit the added salt altogether. 


Sugar: Both fine granulated and brown sugar. The brown can be light or dark. If it’s dark the cookies might spread a bit more than what you see in the photos. 


Peanut Butter: Use a generic brand (not homemade) that does not separate when left in the jar. I use JIF natural. You can use creamy or crunchy here. 


Salt: fine sea salt, NOT table salt. 


Egg: Just one large egg. I haven’t yet experimented making these egg-free but if I were to, I’d use 1 tablespoon ground flaxseed and 1 tablespoon of water. 


Vanilla: Pure vanilla extract or vanilla bean paste. 


Leavening: Both baking soda and powder  here, one to help them spread and one to help them rise up, then crack. Check the dates on the jars, make sure it’s still fresh! 


Oat flour: I use store-bought, either Arrowhead Mills, Bob’s Red Mill or (the most affordable and just as great) Anthony’s. I have never had success making my own oat flour, perhaps because I have a standard food processor that cannot ‘mill’ it fine enough. 

How to make Oat Flour PB Cookies 

Start by partially melting the butter. You can do this in a microwave for 1 – 1.5 minutes or over the stove. Stop when the butter is about two thirds melted and can be ‘creamed’ 

Add the flavorings and whisk into the butter. Adding them to the fat portion of the dough brings the flavors out more 

Pour in the sugars and whisk, very well. You’ll see the mixture start out grainy and separated and as you whisk it will turn shiny and cohesive 

Measure in the peanut butter (this is one of those instances where a scale is wonderful because you won’t have to deal with scraping it out of a measuring cup!) and whisk it in.

Crack in the egg and whisk very well 

Add the oat flour, baking powder and soda and switch to a rubber spatula. Stir until combined 

Uncovered, let the dough chill in the fridge for one hour (if you need to leave it longer, cover it) 

Preheat the oven and prep two cookie sheets by greasing them then lining them with parchment paper (the grease keeps the parchment paper in place) 

Portion the cookies into 1.5 tablespoons to 2 tablespoons of dough each. 

If you like, you can roll them in granulated sugar before baking (I add a pinch of fine sea salt to the sugar and whisk before rolling so you get a nice sweet/salty flavor) 

In the oven the cookies will spread quickly, then puff up and crack. Once they have done so and have golden-ish edges, take them out. They’ll cool for about ten minutes on the pan then you can eat them =) 


Make Ahead Tips 

The dough needs an hour to chill (uncovered) in the fridge before baking. But if you like, you can leave it overnight – just cover it in plastic wrap to seal. 

If you’d like to scoop the cookies and store them in the freezer, make the dough then chill the dough for an hour. Portion the cookies onto a parchment lined plate or tray and freeze them until solid, about 15 minutes. Then transfer to a ziplock bag to freeze. 

You can bring the cookie balls to room temperature and bake as directed, or preheat the oven to 325 F and bake them for 15 minutes or until golden and the centers have cracked. 


Chocolate Chip Oat PB Cookies 

You’re always welcome to add chocolate chips or chocolate chunks! Bear in mind that chunks, which melt beautifully in the oven unlike chocolate chips, will push the cookies to spread even more. 


Oat Flour Peanut Butter Cookie Recipe 

Oat Flour Peanut Butter Cookies

Chewy, crinkle peanut butter cookies gluten free and made with oat flour!
Prep Time: 15 minutes
Cook Time: 12 minutes
Chill Time: 1 hour
Yields: 14 large cookies
5 from 8 votes


  • 113 g or ½ cup unsalted butter
  • 100 g or ½ cup granulated sugar
  • 100 g or ½ cup brown sugar
  • ½ tsp fine sea salt
  • 1-2 teaspoons pure vanilla extract
  • 1 large egg
  • 165 g or ⅔ cup crunchy peanut butter generic brand that does not separate
  • 1 teaspoon baking soda
  • ½ tsp baking powder
  • 195g or 1 ½ cups oat flour


  • In a heatproof bowl, melt the butter in the microwave until it’s almost but not fully melted (about 1 minute at 100% power - if the butter was very cold you might need another 30-45 seconds).
  • Add the sugars and the vanilla and salt and whisk very vigorously, until the mixture starts to turn cohesive and shiny.
  • Add the peanut butter and whisk to combine.
  • Add the egg and whisk very well.
  • Fold in the oat flour, baking powder and soda and stir until there’s no visible flour bits.
  • Set the bowl in the fridge, uncovered for one hour. If you need to leave it longer, cover with plastic wrap to seal.
  • Preheat the oven to 350 F. Line two baking sheets with parchment paper.
  • Scoop the dough into 1.5 - 2 tablespoons of dough per cookie, leaving at least an inch diameter of space around each cookie as they will spread.
  • Bake for 10-12 minutes, until the edges are slightly golden and the cookies have puffed up and cracked.
  • Store cookies in an airtight container at room temperature.

Did you make this recipe?

Share & tag me on instagram @buttermilkbysam


Rate + Review

What do you think of this recipe?

Your email address will not be published. Required fields are marked *

Recipe Reviews

  1. 5 stars
    My new favorite peanut butter cookies!
    The chewiness is unmatched by any other cookie I’ve made; it was my first time using oat flour. I found 13 minutes worked best in my oven. Loved that I didn’t have to break out the mixer for them too!

  2. Can we substitute oat flour with 1:1 gluten free flour or almond flour? What would you suggest as a good substitute for oat flour? Thanks!

  3. Potentially really dumb question ????. If I don’t have flour, could I blend oatmeal until it’s super fine in my vitamix? ????

    • So i’ve never had success doing this but others have done it with my oat flour blondie/brownie recipe and it worked for them. That said there’s more liquid in those so I see it being less of an issue. I guess my answer is, I don’t know tbh!

  4. will this recipe work with rye and whole wheat flour? i don’t have oat flour in hand but definitely want to try. lookin so good as always!

    • I am not sure about rye but I would definitely say no to the whole wheat flour; the amount of gluten in the whole wheat will make for a tough dry cookie and they won’t spread properly

  5. Hi, I just have a question: the only peanut butter I use is natural, would that totally ruin the recipe or is it worth giving it a try?

    • Is it a generic brand that’s ‘natural’? I used Jiff Natural for these and it worked great. If it’s pure peanut paste (like no added ingredients) I suspect it will alter the texture of the cookie.

  6. I love the sound of these peanut butter cookies and have bought oat flour and will make them this weekend. You are the queen of browning butter, so many of your recipes call for that, which really elevates them to another level of deliciousness. I have not seen it in this recipe which surprised me, any reason and do you think it would be ok to do.
    I’m on the browned butter band wagon now, you have converted me!

    • Hi! I love that you are just as big of a fan of brown butter as I am ;p
      You pose a good question, my goal with this recipe was to create a peanut butter cookie that was big, crinkly and super chewy and I knew oat flour would get us there. When it comes to browning butter, other adjustments have to be made: you need to start with more than the recipe calls for and you have to makeup for the lost moisture (I sometimes do this with sour cream). I suppose the answer is, I just didn’t think of it for these! You can try it but I wouldn’t expect the same result or texture (although the flavor might be improved 😉 )

  7. Love! I love this one-bowl stir-it-all-together Peanut Butter Cookie! Sam has turned me into an oat flour convert and this cookie is probably my favorite!