1 (9 inch) prepared chocolate cake
1 (3 ounce) package instant lemon pudding mix
1 cup boiling water
1/4 cup orange juice
1 teaspoon lemon zest
1 tablespoon water
In a large bowl, cream together the sugar, orange juice and lemon zest. Stir in boiling water, orange juice and lemon zest. Beat slightly.
Pour mixture into the prepared pan. Bake in the preheated oven for about 45 minutes, or until a toothpick inserted into the center of the cake comes out clean. Cool completely before cutting into squares to frost.