Butter Sponge Cake - cooking recipe

Ingredients

1/2 lb. sweet butter (unsalted)
6 eggs, separated
1 lemon rind zest
juice of 1 lemon
2 tsp. baking powder
2 c. flour
1 c. sugar
6 egg whites, stiffly beaten

Preparation

Cream butter, sugar and egg yolks. Blend in mixer on slow speed for 10 minutes. Add flour, baking powder, lemon juice and grated lemon rind. Carefully fold in stiffly beaten egg whites. Pour into prepared 9 x 13-inch pan. Bake in preheated 350\u00b0 oven for 35 minutes or tester comes out clean.