Cooking spray
6 oz. bittersweet chocolate, roughly chopped
1/2 c. (1 stick) butter
1/2 c. smooth peanut butter, plus 3 tablespoons, divided
1 c. granulated sugar
4 large eggs
1/2 c. unsweetened cocoa powder, preferably Dutch process
3/4 c. chocolate chips
6 tbsp. heavy cream
Step 1
Preheat oven to 350° and grease an 8” springform pan with cooking spray. Place a small saucepan filled about halfway with water over medium heat and bring to a simmer.
Step 2
Place chopped chocolate, butter, and ½ cup peanut butter in a heatproof bowl and set over the simmering pot, ensuring water does not touch the bottom of the bowl. Stir until completely melted. Turn off heat and remove bowl from saucepan.
Step 3
Whisk in sugar, then add eggs, one at a time, mixing well after each addition. Add cocoa powder and whisk until incorporated.
Step 4
Pour batter into prepared pan and smooth top. Bake until just set in the middle and top is no longer shiny, 30 to 35 minutes. Let cool.
Step 5
Make ganache: Place chocolate chips in a small heatproof bowl. In a small saucepan over medium heat, bring cream to a simmer, then pour over chocolate. Let sit 1 minute, then whisk until smooth.
Step 6
Place remaining 3 tablespoons peanut butter into a small microwave safe bowl and microwave until melted, about 15 seconds.
Step 7
Remove sides of springform pan from cake and place on a plate or platter. Pour ganache over cake and smooth with an offset spatula.
Step 8
Using a small spoon, spoon peanut butter in horizontal lines on top of ganache all the way down the cake. Use a toothpick to drag vertical lines through the ganache and peanut butter across the cake. Alternate dragging from top to bottom, then bottom to top with each line. Let set 15 minutes before slicing.