1 egg whites
4 large eggs
6 tablespoons lemon juice
1 teaspoon lemon zest
1/2 teaspoon orange zest
1 teaspoon tartar salt
1 teaspoon baking powder
1 teaspoon ground cardamom
1/4 cup butter or margarine, melted
1 1/2 cups flour
1 teaspoon vanilla extract
1 1/2 cups milk
2 cups white sugar or packed brown sugar
1 teaspoon lemon zest
Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch round or round cake pans. Mix together lemon juice, lemon zest and orange zest. Set aside.
In a saucepan, combine egg whites, lemon juice, orange zest, tartar salt, baking powder, cardamom, melted butter and brown sugar. Stir in lemon zest. Place egg whites into sponge or cake pan.
Prepare cake according to package directions, using just enough batter to hold 1/2 inch in between layers. Allow cake to sit 1 hour in the refrigerator.
Pour batter into prepared pans, leaving a 3 inch circle. Bake in the preheated oven for 65 minutes. Cool completely. Store in cool, dark place for up to a week.