Cover your cake in candy bars and whipped cream for the best frosting

For some grown-ups, conventional candy bars can be too sweet and concentrated in sugar on their own. But chopped and sprinkled over unsweetened whipped cream, they make an idea topping for a simple white sheet cake.

This cake is pure convenience store kitsch. Inspired by cakes my school cafeteria would serve at lunch time, fluffy white cake gets poked and drizzled with a butterscotch sauce (a homemade one in this recipe), then covered in whipped cream and sprinkled with chopped Butterfinger or chocolate-covered toffee candy bars. The candy bars provide essential crunch and notes of toffee or peanut butter and chocolate to complement the butterscotch sauce on the cake.

This is a fridge cake, so keep it cool until you’re ready to serve it or else the whipped cream might melt all over the place. And with most cakes like this, the longer it sits to meld flavors, the better it gets.

Candy Bar Sheet Cake

1 hour and 20 minutes, plus 1 hour chilling. Serves 12 to 16.

Ingredients
For the cake:

• Nonstick baking spray
• 2 cups all-purpose flour
• ¼ cup dry milk powder
• 3 tablespoons cornstarch
• 1 tablespoon baking powder
• 1 teaspoon fine sea salt
• 2 cups granulated sugar
• 1 cup whole milk
• ½ cup vegetable oil
• 1 tablespoon pure vanilla extract
• 5 large egg whites

For the butterscotch sauce and frosting:

• 1 cup packed light brown sugar
• ½ cup whole milk
• 4 tablespoons unsalted butter
• ¼ teaspoon fine sea salt
• ⅔ cup sweetened condensed milk
• 1 tablespoon pure vanilla extract
• 1 cup chilled heavy cream
• 2 Butterfinger or Heath candy bars (2.1 ounces each), roughly chopped

Instructions

1. Heat the oven to 325 degrees. Grease a 9-by-13-by-2½-inch metal baking pan with baking spray.
2. In a large bowl, whisk together the flour, milk powder, cornstarch, baking powder and salt. In a medium bowl, whisk together the sugar, whole milk, oil, vanilla and egg whites until smooth. Pour the liquid ingredients over the dry ingredients and whisk until just combined. Pour the batter into the prepared pan and smooth the top. Bake until pale golden brown on top and a toothpick inserted in the center of the cake comes out clean, about 40 minutes.
3. While the cake is in the oven, make the butterscotch sauce: Combine the brown sugar, whole milk, butter and salt in a small saucepan and melt over low heat. Increase the heat to medium and cook, stirring often, until the sauce thickens, about 8 minutes. Remove the pan from the heat and stir in the sweetened condensed milk and vanilla. Pour the sauce into a bowl and let cool to room temperature or refrigerate until no longer warm.
4. Remove the cake from the oven and transfer to a wire rack. Let the cake cool for 20 minutes, then use a 1/2-inch-wide wooden dowel or handle end of a wooden spoon to gently poke holes three-quarters of the way down the cake and spaced about 1 inch apart. Pour the butterscotch sauce all over the cake, aiming to get most of it to soak into the holes in the cake.
5. In a large bowl, whisk the cream by hand or with a hand mixer until stiff peaks form. Scrape the whipped cream onto the cake and use a small offset spatula or table knife to spread it evenly over the top. Sprinkle the chopped candy bars all over the cake and chill in the refrigerator for 1 hour before serving from the pan.

Make ahead
The cooled cake can be wrapped in plastic wrap and kept at room temperature for up to 2 days. The butterscotch sauce can be refrigerated for up to 5 days. Return the sauce to room temperature before stirring again and using. The completely assembled cake can be refrigerated for up to 1 day.