Peanut Butter Smith Island Cake

Directions

1. Make the icing: In a medium saucepan over medium heat, add the butter, chocolate, granulated sugar, heavy cream, and corn syrup, stirring constantly until the butter and chocolate are melted. Continue to cook, stirring occasionally, bringing the icing to a boil and continuing to cook for another 2 minutes (or until it reaches 220°F). Remove from heat and whisk in the vanilla extract. Add salt to taste. Set aside, uncovered, to cool for at least 2 hours.
2. Make the cake: Preheat oven to 350°F. Grease and three 9-inch cake pans and line with greased parchment paper rounds; set aside.
3. In a large bowl, whisk the flour, powdered peanut butter, baking powder, baking soda, and salt; set aside.
4. In a second large bowl, using a handheld or stand mixer fitted with a paddle attachment, beat the butter and sugar together on high speed until light and creamy, about 2 minutes. Add the peanut butter and beat another 2 minutes. On medium-high speed, add vanilla then 1 egg at a time, beating well after each addition.
5. Add the flour mixture in three additions alternating with two additions of buttermilk (beginning and ending with the dry ingredients) and mix each addition until just combined.
6. Pour less than 1 cup (200–210g) of batter into each of the three prepared cake pans and spread evenly (cover rest of batter loosely at room temperature). Bake for 11–12 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool in the pans for a couple minutes before inverting onto parchment paper. Peel off the parchment and place back in the pan with more grease. Repeat with the remaining batter until you have 9 layers. Allow cake to cool completely, about 1 hour.
7. Assemble the cake: On a large flat surface or serving platter, place one layer of cake. Top with1/4 cup of icing, spreading evenly to the edges, then repeat with the rest of the cake layers and icing. Decorate with sprinkles, if desired, then set aside for at least 1 hour to let the icing set before slicing and serving.