2cupsmix of fresh berriescut larger berries to be equal in size to smaller berries
Frosting Ingredients
16ouncesheavy cream
8ouncesmascarpone cheese
1cuppowdered sugar
1teaspoonvanilla
Instructions
Make the Cake
Preheat oven to 350°F. Prepare an 11x15x2 sheet cake pan by thoroughy greasing the bottom and sides with butter.
In a medium bowl, mix together the cake flour, baking powder, and salt. Set aside.
Whisk together the milk, sour cream, egg whites, and vanilla. Set aside.
In a large bowl, using a hand mixer, cream together the sugar and softened butter until well combined.
Add 1/3 of the dry ingredients to the butter-sugar mixture and mix just until combined.
Add 1/2 of the milk mixture and stir until just combined.
Continue with another 1/3 of the dry ingredients, mixing just until combined.
Stir in the other half of the milk mixture.
Mix in the last 1/3 of the dry ingredients until just combined.
Add the tablespoon of flour to the fruit and toss. Then, using a spatula, gently stir them into the cake batter.
Spread the cake batter into the prepared cake pan. Bake at 350°F for 35 to 40 minutes, until a toothpick comes out clean. Allow to cool completely, at least 2 hours, before frosting.
Make the Frosting
In a large bowl, add all of the frosting ingredients. Using an electric hand mixer, whip until stiff peaks form.
Spread the frosting over the cooled cake.
Optional: Decorate with additional fruit.
Notes
This cake can be made the day before you plan to serve it and the frosting will remain fluffy and creamy.
Store the cake in the refrigerator. It will be good for up to 3 days.
You can subsititute frozen berries without needing to thaw them first. Simply toss them in the flour and mix them into the batter just as you would fresh fruit.