Beat the egg whites (at room … Add blueberries and lemon juice, and stir gently to coat berries. Bake as directed on package. Spoon half of the egg white mixture on the batter in … Next, spread blueberry pie filling on top of cake. Pour into the pie crust. In a large bowl, stir together the sugar, cinnamon and cornstarch. Beat egg whites, adding a pinch of salt and 200 g of sugar slowly as soft peaks are starting to form. Cool. Pour batter into a greased 13x9 inch pan. Follow directions on package of cake mix. Beat until stiff.