Double Fudge Cake

3 eggs
1 1/2 C sugar
1/2 C milk
1 1/2 C all-purpose flour
1/2 tsp baking powder
1/4 tsp salt
1 C butter or margarine
4oz semisweet chocolate
1 (16oz) can prepared chocolate frosting

Preheat oven to 350. Whisk eggs, sugar and milk in medium bowl. Mix flour, baking powder and salt in large bowl. Pour egg mixture into flour mixture; mix well. Grease 9x13" baking pan. Melt butter and chocolate in top of double boiler set over gently simmering water. Cool slightly. Blend chocolate mixture into batter. Pour into prepared baking pan. Bake 35 minutes or until toothpick inserted in center comes out clean. Cool cake in pan on wire rack; remove. Spread top with prepared frosting.