Blueberry upside down cake

Blueberry Upside Down Cake 

Ingredients: Makes 24 servings.
 * 1/2 cup butter
 * 1 cup brown sugar
 * 2 cups blueberries
 * 1 cup flour sift before measuring
 * 1 teaspoon baking powder
 * 1/8 teaspoon salt
 * 3 eggs separate out yolks
 * 1 cup sugar
 * 1/2 cup milk

Directions: Melt butter in large baking pan. Spread brown sugar in pan and arrange blueberries on sugar. Mix dry ingredients together. Beat egg yolks until light, gradually adding sugar. Add dry ingredients and milk alternately. Fold in stiffly beaten egg whites. Pour into pan. Bake at 375 degrees for 30-35 minutes. Immediately turn upside down on serving dish.