Preheat oven to 350°F. Prepare a 9x13-inch baking pan with nonstick cooking spray or line with parchment paper for easier removal and clean up. Set the pan aside.

In a medium bowl, whisk together 2 cups all-purpose flour, 1 ¼ teaspoon baking powder, and ¼ teaspoon kosher salt. Set aside.

In a large bowl, combine 4 large eggs, 2 cups granular sugar, and 2 teaspoons pure vanilla extract. Start mixing on low speed with a hand mixer just until the ingredients are combined, then increase to medium speed and continue beating for 3 minutes, or until the mixture is pale, thick, and slightly ribbon-like when you lift the beaters. This technique incorporates air evenly without creating large bubbles.

In a microwave-safe bowl, combine 1 cup whole milk and ¼ cup unsalted butter. Microwave on high in 30-second intervals until the butter is melted and the milk is steaming. Do not let the milk boil. Set aside.

Add the dry ingredients to the egg and sugar mixture and mix on low speed just until smooth, about 1 minute.

Pour the warm milk and butter mixture into the batter. Mix on low speed just until the ingredients are incorporated, scraping down the sides of the bowl. Do not overmix the batter.

Pour the batter into the prepared pan and smooth the top. Bake 25-35 minutes, or until a cake tester or toothpick inserted in the center comes out clean. The top of the cake will turn golden brown while baking. Allow the cake to cool completely on a wire rack.

For the peanut butter layer, beat together 1 ¼ cups creamy peanut butter, ½ cup powdered sugar, ¼ cup softened unsalted butter, ¼ cup heavy cream, and ½ teaspoon pure vanilla extract until creamy and smooth. Spread the mixture evenly over the cooled cake. Chill in the refrigerator for 30 minutes to set.

For the chocolate layer, melt (6) 1.5-ounce bars of milk chocolate and 2 tablespoons unsalted butter together in the microwave in 30-second intervals, stirring until smooth. Let cool slightly, then spread evenly over the peanut butter layer.

Chill the cake for at least 1 hour to set all layers before slicing and serving. ENJOY!