White Cake with Malted Milk Chocolate Frosting
Moist, tender white sheet cake with malted milk chocolate buttercream frosting is an unexpected treat, perfect for any upcoming occasion.
- White Cake
- 1 cup Whole Milk, room temperature
- 6 Large Egg Whites, room temperature
- 1 tsp. Vanilla Extract
- 2.25 cups Cake Flour
- 1.75 cups Sugar
- 4 tsp. Baking Powder
- 1 tsp. Salt
- 12 tbsp. Unsalted Butter, cut into small cubes and softened
- Malted Milk Chocolate Frosting
- 1/4 cup Granulated Sugar
- 2 Large Egg Whites
- Pinch Fine Sea Salt
- 12 tbsp. Unsalted Butter, softened and cut into 1-tablespoon pieces
- 6 oz. Milk Chocolate Chips, melted and cooled to 85-100 degrees F.
- 1/2 tsp. Vanilla Extract
- 1/4 cup Malted Milk Powder
Adjust an oven rack to the middle position and preheat the oven to 350 degrees F. Grease and flour a 9x13-inch baking pan. If you want to remove the cake from the pan, grease it, line it with parchment, then grease and flour the parchment.
Whisk the egg whites, milk and vanilla together in a small bowl. Then, in a stand mixer with the paddle attachment, mix the flour, sugar, baking powder and salt together on low until combined. Then add the butter a few small cubes at a time and mix until there are only pea-sized pieces of butter left.
Pour about half of the milk mixture into the dry mixture and increase the speed to medium-high. Beat until light and fluffy.
Now, reduce speed to medium-low and pour in the rest of the milk mixture and beat until incorporated, about 30 seconds. The mixture may look broken at this point. Beat for several seconds by hand.
Pour the batter into the prepared baking pan and smooth the top with a silicone spatula. Tap the pan a few times on the counter to settle the batter and remove any air pockets.
Bake the cake for about 25 minutes. Test with a wooden skewer or cake tester, it should come out mostly clean but with a few crumbs attached. Let cake cool in the pan, set on a wire cooling rack, until completely cool.
Malted Milk Chocolate Frosting
Start by setting up a saucepan with a couple inches of water to simmer.
Now, melt the six ounces of chocolate chips in the microwave, on 50% power for about 1 minute. Stir the chocolate halfway through. Once the chocolate is melted, set it aside to cool down to between 85 and 100 degrees F. before adding it to the frosting.
Combine the egg whites, sugar and salt in the bowl of your stand mixer and set the bowl on top of the simmering water. Whisk gently but consistently until the mixture is slightly thicker and foamy. Temp it, we are looking for 150 degrees. This should only take about 2-3 minutes.
Take the bowl to your stand mixer fixed with the whisk attachment. Beat the mixture on medium speed until it's the thick and foamy and has slightly cooled – about 1-2 minutes.
With the mixer still running, add the softened butter, one piece at a time and beat until the mixture is smooth and creamy. About halfway through adding the butter, the mixture may look curdled. That's OK. Keep whisking and adding butter.
Once all the butter is added, add the cooled melted chocolate and the malted milk powder. Mix until combined then increase the speed to medium-high and beat until the frosting is light, fluffy and thoroughly combined. Scrape down the sides as needed.
Use an offset spatula to smooth the frosting evenly over the cake.