To make the cake, preheat oven to 350 degrees. Lightly spray the KitchenAid® Streamline Ceramic (4.2 qt) baking dish with cooking spray.
In a bowl, combine flour, baking powder, and salt; set aside.
Cream butter and sugar together in the bowl of a stand mixer fitted with the paddle attachment. Beat in the egg yolks until just combined. Slowly add the dry ingredients to the wet ingredients in small increments until the batter is well combined. Add vanilla and mix until combined.
Pour batter into the prepared ceramic baking dish. Bake for approximately 20-25 minutes, until a toothpick comes out clean when stuck in the center. Remove from oven and cool.
To make the frosting, combine sugar and butter in the bowl of a stand mixer fitted with the whisk attachment. Mix on low speed until well combined, then increase speed to medium and beat for an additional 3 minutes. Add cocoa powder and cream and continue to beat on medium speed for 1 minute.
Once cake is cool, frost the cake and top with candy. Serve with a big glass of milk!