Lemon Butter Cake
1 cup unsalted butter, at room temperature
2 cups sugar
2 tsp lemon zest
1 1/2 tsp lemon extract
Juice of one lemon
7 egg whites
3 cups cake flour (if using AP flour, replace 6 tbsp of flour with corn starch)
4 tsp baking powder
1/2 tsp salt
1 1/4 cup milk
1 cup blueberries
1 cup cranberries
2 cups mascarpone cheese
2 tbsp sugar
3/4 cup heavy cream
Prepare the cake:
Preheat oven to 350ºF, butter the bottom of two 9 inch cake pans, line the bottoms with parchment paper and butter the paper.
Sift flour, salt and baking powder together in a medium bowl.
Cream the butter and sugar, add lemon zest, extract and juice. Add the egg whites 2 or 3 at a time and continue beating until well blended.
Add 1/3 of dry ingredients to butter mixture and beat. Add half the milk and beat. Repeat and then finish with remaining 1/3 of dry ingredients.
Divide batter into cake pans and top with berries.
Bake cake for 35 minutes or until wooden toothpick comes out clean.
Cool on racks in pan for 10 minutes, remove cakes from pans and let cool on racks until completely cool.
Prepare the filling:
Mix mascarpone cheese with sugar until well blended, add cream and continue to beat until stiff in a stand mixer with a whisk attachment.
Assemble the cake:
Place cake layer, berry side up, on serving plate. Top with mascarpone filling and spread over layer. Put second layer, berry side up, on top of filling. Dust with powdered sugar.