Chocolate Brownie Cake with Peanut Butter Frosting

Tips for Chocolate Brownie Cake with Peanut Butter Frosting

How to turn brownies into cake layers

The brownie cake recipe is adapted from the ultra talented Erin of Cloudy Kitchen. She took classic brownies and made them sturdy enough for a layer cake while still remaining rich and fudgy.

The brownie cake layers use a high amount of both melted semisweet chocolate and cocoa powder for an intense chocolate flavor. They also use a combination of butter and oil for the best flavor and moist texture. Tons of eggs help add richness and structure, as does the addition of baking powder (which is not included in my traditional brownie recipes).

Which cake pans are the best?

I love my Fat Daddio anodized aluminum cake pans. They release cakes of all variety easily and don’t dry out the edges. Whatever you do, never bake a cake in a dark colored pan. It’ll likely over bake and be too brown and dry at the edges.

Can I use 8-inch cake pans instead?

This recipe uses three 6-inch cake pans for a beautifully tall cake with the perfect amount of fudgy brownie goodness in every slice.

I haven’t tested this, but can try using two 8-inch cake pans and start checking for doneness at 25 minutes. The cake will obviously be much shorter.

How to Make Creamy Peanut Butter Frosting

Start with butter that’s softened to room temperature and a whole cup of creamy conventional peanut butter. Not the “natural” stuff that doesn’t contain any added added oil. I like to use Skippy.

Why? That added oil helps prevent the peanut butter from separating so it stays homogenous which is definitely what we want for buttercream. If you use a natural peanut butter product that only contains ground peanuts then your buttercream may break and not taste as peanut buttery.

Make sure to sift your powdered sugar before using for the smoothest creamiest buttercream. For even creamier buttercream, try using organic powdered sugar with tapioca starch. It dissolves into the frosting better than the traditional cornstarch so you don’t get any grittiness. For more buttercream tips check out this post.

How to Assemble & Decorate a Layer Cake

Place one cake layer on a cake stand or serving plate. Spread with about 1/2 cup of the frosting. Repeat with the remaining two cake layers, leaving the top layer flat side up. This ensures the top of the cake is level with clean edges.

Apply a thin layer of crumb coat icing to the entire surface of the cake, scraping away any excess with an offset spatula or bench scraper to create a spackle-like coating. Be sure not to scrape any crumby icing back into your clean bowl of icing. A cake turntable makes easy work of this. Refrigerate the whole thing until hard, about 15 to 20 minutes.

While the crumb coat is in the fridge make the chocolate drip. You want it to cool until it has thickened but is still pourable. But not so thin that it runs clear down the sides of the cake. It’s a fine balance! The amount of time it takes for the ganache to cool to this consistency will depend on the temperature of your kitchen and the size and shape of your bowl.

Whatever you do, don’t place the ganache drip in the fridge to cool. This will create uneven chunks of cooler ganache next to runnier warmer bits. Test the consistency of the drip by pouring down the side of a glass. If it’s too thick, microwave for 5 to 10 seconds then stir. If it’s too thin, allow to continue to cool.

Can this recipe be made into cupcakes?

Almost any cake recipe can be converted into cupcakes. Check out my full guide on how to convert cake to cupcakes (and vice versa!). 

How to Make the Cake Ahead of Time

The brownie cake layers can be stored in the fridge, wrapped tightly in plastic wrap, for up to 2 days before assembling.

The frosting can also be stored in the fridge, wrapped in plastic wrap, for up to 1 week. Allow to come to room temperature before re-whipping with an electric mixer until smooth and creamy again.

The assembled and frosted cake can be stored, covered, at room temperature for up to 1 day or in the fridge for up to 3 days.