German Marble Cake - cooking recipe

Ingredients

1 cup butter (Magarine)
1 cup sugar
3 eggs
3 cups flour
1 teaspoon baking powder (originally, 1 teel.)
1 tablespoon lemon juice
200 g chocolate (about 1 cup)

Preparation

Beat butter and sugar until fluffy.
In a separate bowl, beat eggs until frothy, and gently add to butter and sugar.
Add in flour, baking powder and lemon juice.
Pour 2/3 of the batter into a greased and floured cake pan (I'm assuming a 9 inch spring form or 13x9 pan would work.)
Melt the chocolate, and mix into the remaining batter. (You may need a tablespoon of cream to thin the chocolate as you melt it.) Pour over the batter in the pan, and make a marbled pattern using a fork.
Bake for 60 minutes at 350\u00b0F.