The peanut butter chocolate cake is a super simple chocolate cake made with melted chocolate and finished with natural peanut butter frosting and sprinkles!
Preheat the oven to 350 ºF (175 °C). Butter and flour a 9x9-inch square brownie pan and line the bottom with a square of parchment. I like this square pan from Amazon.
In a bowl, whisk together the flour, baking powder, salt, and baking soda.
In a separate bowl, cream together the butter and the sugars until they are well blended. You can do this with a handheld electric mixer (I'm obsessed with the electric mixer from Braun on Amazon) or a stand mixer (like this KitchenAid Artisan model on Amazon).
Add the eggs, one at a time, mixing well after each addition. The mixture will be light and fluffy. Add the vanilla
Add the dry ingredients, alternating with the sour cream, until the batter is just combined. Add the melted chocolate.
Smooth the batter in the prepared pan and bake for 30 to 35 minutes or until set and firm. I like to check with a metal cake tester like this one on Amazon to see if the cake is baked through in the middle.
Set aside to cool for 15 minutes then unmold on a wire rack to cool completely before frosting.
Natural peanut butter frosting
In a large bowl, using a handheld electric mixer, combine the natural peanut butter and the icing sugar to form a thick, crumbly mixture.
Add the softened butter and the vanilla and blend into a thick, spreadable frosting.
Frost the cooled cake with an offset spatula. Use a pastry bag fitted with a large star tip to decorate (like this 1M start tip from Wilton on Amazon). Decorate with chocolate curls and sprinkles.
Notes
I used a Canadian brand of natural smooth peanut butter with sea salt (that contains only peanuts and salt), but Trader Joe's natural creamy salted peanut butter should work and it's available on Amazon.
For the dark chocolate, I used Cacao Barry Ocoa 70 % dark chocolate.