Filed under: Buttermilk Basics
May 4, 2023

Nut Butter Penuche Frosting

Penuche frosting, a brown sugar ‘frosting’ , with a nutty twist. This easy recipe is made entirely in a pot and in less than ten minutes. You can use any nut butter you like (homemade nut butters too!). Penuche thickens as it sets and will be akin to a thick glaze - the perfect nutty topping to any brownie, blondie or snacking cake.

5 from 1 vote
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My introduction to penuche frosting came via food52 and this beautiful banana cake. Look how pretty that stuff is swirled around!! The first time I made it (without the cake and this was some 8-9 years ago, pre-buttermilk) I either over or undercooked the sugar and butter mix and I couldn’t use it. I figured this was some magic that my baking abilities weren’t quite up for yet. Luckily we’ve come a long way in the past decade and I’m ready to give you the confidence and guidance to make it successfully, hopefully on the first try! 

And also, hi it’s me – we’re doing an unconventional twist on it ok? =) It’s gonna be good. 

I first made this as a peanut butter penuche and later as a hazelnut. It’s such a versatile topping and is going to be on a lot of future buttermilk desserts so I wanted to give it it’s own page.

P.S. I’m going to be saying peanut butter penuche a lot but know that it works with all nut butters.


What.. is.. penuche… frosting? 


Pen-oo-che is and means fudge. Which is very good because this ‘frosting’ tastes and is made like a fudge (cooking butter and sugar together) but unlike fudge, penuche (or pannucci in italian) has no chocolate and is made with brown sugar rather than granulated. In the American south, penuche fudge is ‘brown sugar fudge candy’ (which seems a very redundant name to me, even if appetizing, lol).  


Penuche frosting is called frosting but consistency wise is very different; I liken it to something between fudge and a thick basic powdered sugar/liquid glaze. 


You’ll usually find penuche frosting as a basic brown sugar/butter/powdered sugar concoction but we’re changing it up to add more flavor by adding in nut butter. So far I’ve done peanut butter and hazelnut butter (the latter was homemade) but I’m confident it’ll work with any nut butter. 


How to make a peanut butter penuche frosting

 This is a simple recipe but I want to break it down a bit so you understand what’s happening (and it will happen very quickly) and why it needs to all happen in stages: 

Melt the butter: have the heat on medium low so it doesn’t melt too quickly and brown. Wait till it’s almost entirely melted to move to the next step. 

Cook the sugar & butter: add the brown sugar to the melted butter and stir, then give it a couple of minutes to cook without fussing over it so the sugar can dissolve.

Cook the milk: After a quick whisk to the butter/sugar, add the milk. This is when the consistency is going to change, you’ll see it go from being separated and bitty to smooth and shiny. Let it cook (boil) for just a couple of minutes again, then whisk and shut the heat off and add the peanut butter and whisk.

Add the flavorings: Now, salt and vanilla and whisk to combine. It’s still going to be super runny and you’ll be skeptical – trust. Once it’s combined add the first half of the powdered sugar.

Add the powdered sugar, slowly: Begin whisking the sugar in and once it’s fully combined, add the other half. Keep whisking until you can’t see any bits of powdered sugar.

Pour over the bars/dessert: It’s going to be thicker than before you added the powdered sugar but still very thin. Pour over your dessert and smooth it over. It’ll immediately begin to set and if you brush it you’ll disturb the thin, smooth surface. Sprinkle on some sea salt now if you want to.

Wait: give it 30-60 minutes and it’s going to be thick enough to slice into!


What kind of peanut butter or other nut butter should I use for the penuche? 

Honestly, I’m betting anything will work: peanut butter, almond butter, cashew butter, sunbutter… I’ve also made it with homemade nut butters (hazelnut!) but I’d definitely say whatever you use should be very well stirred. So even if it’s natural peanut butter make sure you’ve stirred it well and have a smooth paste (not say, oily bits and/or super chunky dry bits). 

The only spread I’m concerned with (I’ve yet to try it but I have some suspicions) is tahini. Because tahini thickens when stirred I think it could easily mess up the penuche – [I’ll work on it and see what I can come up with 😉 ]

What can I do with a peanut butter penuche? 

It can go on any bar or snacking cake. Brownies, blondies, etc. I have it on a cake in this recipe and it’s wonderful. I think the most obvious and iconic match would be to do a peanut butter penuche on brownies. 

For cake & nut butter penuche frosting, consider a nut butter, vanilla or chocolate snacking cake (again – chocolate cake with a pb penuche frosting? iconic!). 

But oh, you can also spread a bit of it on some cinnamon rolls and turn them into quite the treat. 

Can I make peanut butter penuche ahead of time? 

Nope, because of the way it sets you’ll want to make it after your bars/cake/rolls or whatever you’re using it on is ready. As soon as the penuche frosting goes on you’ll let it be and it will thicken and solidify. 

Troubleshooting penuche frosting 

The frosting split (is greasy instead of smooth and shiny) 

You might need a tad more milk, add a tablespoon at a time and whisk well to see if it comes back together.  


Nut Butter Penuche Frosting

Brown sugar fudge frosting made with any nut butter!
Prep Time: 5 minutes
Cook Time: 10 minutes
Rest Time: 1 hour
5 from 1 vote


  • 57 g unsalted or salted butter cold is fine
  • 65 g or ⅓ cup brown sugar
  • 60 g or ¼ cup whole milk
  • 100 g peanut or any nut butter roughly scant ½ cup
  • Pinch fine sea salt
  • 1 small dash of pure vanilla extract
  • 225 g or 1 ¾ cups powdered sugar preferably one made with tapioca not cornstarch (sifted beforehand)


  • In a pot, add the butter and set it over medium low heat. Once it has melted, add the brown sugar and whisk.
  • Let it cook for a couple of minutes, you’ll see it bubble as if it’s boiling and give it quick whisk then add the milk and whisk it in.
  • Cook it with the milk for another 2 minutes, this time without stirring. You’ll see bubbling again. Turn off the heat and add the nut butter, salt and vanilla - whisk it quickly.
  • Add half of the sugar and whisk until you can’t see any more bits of powdered sugar, then add the other half and whisk again until you have a thick, smooth but very runny ‘frosting’.
  • Pour over your prepared bars/brownies/blondies or cake and let cool completely. It’ll seem like it’s going to be a mess but trust - after about an hour it’s going to thicken and solidify enough for you to be able to slice it.


This will make enough for a generous, thick layer covering a dessert made in an 8 or 9" square pan. If you've made your brownies/blondies/snacking cake in a 9x13" pan this will give them a decent, thin layer. 

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