Brownie Peanut Butter Cake

Go to the tailor and let a few inches out on the waist of all of your pants because this cake is worth it. I wanted to make my new hubby a cake that tasted like a large reeses peanut butter cup since he loves reeses. So I searched far and wide and found this recipe by Sprinkle Bakes.

This cake tastes exactly like a huge reeses peanut butter cup! It is also very rich, so I would cut small pieces. Most people couldn’t finish a regular slice of this cake. I like to zap a piece in the microwave for 20 seconds and then top it with a scoop of vanilla ice cream. Yummy dum dum!

So, before I go into the details of making and assembling the cake, I would like to say…I screwed up. BUT this is just evidence that you can mess up and fix things and cover it up, and still get an OK looking cake. I’ll tell you the steps I messed up…

Brownie Peanut Butter Cake – Brownie Layer

Yield:  three 9 inch layers of brownie


  • 1 1/2 cups butter
  • 6 ounces unsweetened baker’s chocolate, chopped
  • 3 cups granulated sugar
  • 5 large eggs
  • 1 1/2 teaspoons vanilla extract
  • 1 1/2 cups all-purpose flour
  • 3/4 teaspoon salt
  • 1/2 tsp. baking soda


  1. Line the bottom of three 9 inch round pans with parchment paper. Grease and flour the sides of the pan. I did not line the bottom of the pan with the parchment and the brownie stuck to the pan. You’ll see it in the photos below, the brownie was broken into pieces and I had to repiece it – but it turned out OK!
  2. In a medium saucepan over medium-low heat, melt butter and chocolate; stir until smooth. Transfer to a large bowl and whisk in sugar. Add eggs, one at a time, whisking well after each addition.  
  3. Whisk in vanilla, flour, salt and baking soda.
  4. Pour into the three prepared baking pans. Bake at 350° for 23-25 minutes. Cool for 10 minutes; remove from pan to a wire rack to cool completely.  Wrap in plastic wrap or store in air-tight containers until needed.

Mmmm, look at that delicious shiny crust on the brownie. That’s probably the best part.

Click to Print Brownie Layer Recipe

Now the delicious peanut butter layer…I also messed this part up.

Brownie Peanut Butter Cake – PB Layer

Yield:  two layers of 9 inch cake


  • 6 cups powdered sugar
  • 2 cups creamy peanut butter
  • 1/2 cup butter, melted
  • 1/4 cup (maybe more) heavy cream


  1. Mix together the powdered sugar, peanut butter and melted butter in a standing mixer fitted with the paddle attachment.  Mixture will be crumbly.  Add cream 1 tablespoon at a time until the mixture becomes a consistent workable dough.  It should not be crumbly or stick to your fingers.  The mixture should hold together easily when a small amount is squeezed tight in the palm of your hand. 
  2. Divide the dough into two even portions.  Spray one (or two if you have them) 9-inch spring-form pans with cooking spray or line two 9-inch pans with parchment rounds.  Press peanut butter dough into the bottom of the pans evenly, forming the peanut butter layers.  Turn the layers out onto two cookie sheets and place in freezer until frozen solid.

Click to Print Peanut Butter Layer Recipe

I used another smaller pan to help press it down evenly.

I didn’t have two 9 inch springform pans, so I put all the peanut butter layer in one pan. This did not bode well for me because the peanut butter layer really does freeze solid. I figured I would cut it in half after freezing…silly me. I may be an engineer but I guess the common sense part got away from me. I could not cut that thing, so I just stuck it whole in the cake and ate the third brownie layer that was meant to go in between.

Brownie Peanut Butter Cake – Frosting

Yield:  enough for a 5 layer 9 inch cake


  • 1 1/2 cups butter, softened
  • 1 1/4 cups powdered sugar
  • 1/2 cup unsweetened cocoa powder
  • 2 tsp. vanilla extract
  • 1 tsp. espresso powder


  1. Beat softened butter and powdered sugar together in the bowl of a standing mixer fitted with the whisk attachment.  Scrape down the sides of the bowl and beat again until creamy. 
  2. Add cocoa powder and vanilla extract; beat well.  Add espresso powder and beat for 1-2 minutes longer until thoroughly incorporated. I didn’t have espresso powder so I just finely ground espresso. It works just as well. It takes a little bit for the cocoa powder mixture to blend in with the frosting.

Click to Print Chocolate Frosting Recipe

But keep beating until it’s nice and smooth.

Now to assemble the cake…

Cake Assembly

  1. As I said before, I screwed up the brownie layer. So I took a cake circle and put some frosting on it and then put the pieces of the brownie on that. It was like putting together a little brownie puzzle. See?? 
  2. Then spread a thin (very thin!) layer of frosting on that layer. You don’t need a lot, really it’s a sweet cake already. 
  3. Then place your layer of peanut butter on top (in my case, the whole chunk). 
  4. Look my cake is kind of crooked, but you just press it down a little and make some adjustments, then it becomes leveled. I also need to shave off the sides of the peanut butter layer to match the brownie layer. The brownies kind of condensed after baking and the peanut butter layer was just huge. But the best part of it is that you get to eat all the shavings! 
  5. Spread another thin layer of frosting and then place another layer of brownie on top. 
  6. Spread the frosting over the whole cake leaving some for decorating. 

I decorated the cake with rosettes on top and a swirly pattern below (I kind of just made it up and swirled and spiraled). Then I placed reeses cups that I cut in half on top of the rosettes, similar to Sprinkles Bakes.

I used reeses pieces to write 31 on the cake too. Then piped the words in white chocolate on wax paper and refrigerated it until the words set. I placed these on top.

Now, my hubby loved the cake, but thought the peanut butter to brownie ratio was a little off (given another layer of brownie was supposed to be in the cake). I, however, have always thought that reeses peanut butter cup ratios are off (and even peel off the chocolate sides), loved the cake. The ratio was perfect for me. Maybe make it the correct way, or my way, and see what you think…

And another slice for good luck.



7 thoughts on “Brownie Peanut Butter Cake

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