Take your peanut butter and chocolate pairing to the next level with this decadent 6 ingredient peanut butter brownie frosting. In just 15 minutes, you’ll enjoy a frosting that makes even the best brownies better.
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If you want to add extra decadence and elegance to your basic brownies, this six ingredient peanut butter brownie frosting recipe suits your needs. Easy to whip up, this buttercream frosting comes together in just 15 minutes and only requires one bowl to make.
Filled with richness and a lovely light texture, it's the perfect pairing for a dense, fudgy brownie.
What You'll Learn In This Recipe
- My secret to a light and fluffy brownie frosting.
- The best type of peanut butter to use for peanut butter brownie frosting.
- Storage instructions in case you want to make the peanut butter buttercream ahead of time.
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Ingredients You Need
It takes just a few ingredients to make the best peanut butter frosted brownies.
Unsalted butter: For the best frosting, allow the butter to soften to room temperature. The butter should slightly give when you push against it but overall still hold its form. If you’re opting to use salted butter, be sure to adjust the amount of extra salt added to the recipe.
Peanut butter: The best peanut butter for this recipe is a nice creamy one. I would avoid using any “natural” peanut butter because these tend to have separated oil. This oil could damage the consistency of the buttercream frosting by making it too oily.
Confectioners’ sugar: Otherwise known as powdered sugar or icing sugar, this ingredient sweetens the frosting and also is responsible for adding structure. Be sure to measure first, then sift the confectioners’ sugar to achieve the best consistency.
Heavy cream: This ingredient helps thin out the buttercream icing, making it spread much easier. For the longest shelf life on your frosting, use very fresh heavy cream. Always checking the expiration date on the heavy cream will allow your buttercream to last up to one month after preparing it.
How To Make This Recipe
In just a handful of minutes, you can enjoy a peanut butter frosting. Here's how to make it:
1. To begin making the peanut butter brownie frosting, add the butter and peanut butter into the bowl of a stand mixer fitted with a paddle attachment. Turn the mixer on medium-high speed and let it beat these ingredients for 2 to 3 minutes until it's light and fluffy.
Using a silicone spatula, be sure to scrape the sides of the mixer bowl to ensure all the butter and peanut butter is evenly mixed.
2. Next, reduce the speed on the stand mixer to medium-low and add in the confectioners’ sugar. Remember to sift the confectioners’ sugar before adding it to the butter mixture. This will prevent any clumps from forming and ruining the light and smooth texture of the frosting.
With a thick paste formed, it is time to thin out the frosting by adding in the heavy cream. At this point, go ahead and add the vanilla extract and fine sea salt as well.
3. For the best textured frosting, crank the speed on the stand mixer back up to medium-high and allow the buttercream frosting to beat for an additional 5 minutes.
After five minutes, the frosting should be light and fluffy. Don't be tempted to cut this time short!
4. Lastly, using an offset spatula, evenly spread the frosting across a 9 x 9 inch pan of brownies. The offset spatula will allow you to form a lovely wavy pattern on the top of the brownies.
For a smooth look to the frosting, fill a glass of hot water and dip the offset spatula in for a few seconds. Remove the spatula and shake off any excess water.
Then, slowly run the spatula along the top of the frosting to make as smooth of a layer as possible.
- Did you know you can make this frosting ahead of time? Peanut butter brownie buttercream frosting can be stored in an airtight container in the refrigerator for up to 1 month, as long as the heavy cream you used is fresh. Before using the buttercream, allow it to come to room temperature so it spreads easily on the brownies.
- Allow the brownies to cool down before frosting them. If the brownies are still warm, the frosting will melt off.
- Making these delicious peanut butter brownies for a birthday or special occasion? These brownies are perfect for decorating with things like sprinkles, chopped peanuts, chopped Reeses peanut butter cups, chocolate chips, or a drizzle of caramel sauce. Even if there is no occasion, this is a fun way to add some decoration and new flavors to these brownies.
If your butter or peanut butter (or both) is too warm, this can cause the frosting to separate. To avoid this, make sure both ingredients are at room temperature when you begin.
Absolutely. Store the brownies in an airtight container and place them in the freezer where they’ll last for 1-2 months. Allow the brownies to come back to room temperature before serving.
No. Because this recipe uses heavy cream, these brownies cannot be stored at room temperature for extended periods of time. You can leave the brownies out at room temperature for 1-2 hours maximum.
This frosting recipe yields 1¼ cups of frosting, just enough for a nice heavy layer of frosting on a 9 x 9 inch pan of brownies. If you prefer less frosting on your brownies, you can absolutely save extra peanut butter icing for the next batch of brownies you make.
More Dessert Recipes
Peanut Butter Brownie Frosting (6 Ingredients)
- Beat butter and peanut butter in a stand mixer fitted with a paddle attachment on medium-high speed until light and fluffy, about 2 - 3 minutes. Scrape down the sides of the mixer as needed.
- Add confectioners' sugar; mix on medium-low speed until combined.
- Add heavy cream, vanilla extract, and fine sea salt; mix until fully combined.
- Set the mixer to medium-high speed and allow the buttercream to beat for an additional 5 minutes.
- Spread frosting on top of a 9 x 9 inch pan of brownies using an offset spatula.