Duncan Hines has (had ?) a similar recipe on the side of their lemon cake - I've used it on many - changing the cake mix and pudding flavor accordingly. Comes out great every time. They had a recipe for the glaze on the lemon one that was just lemon juice and confectioners sugar - so much better than what they put on the boxes now. Haven't made the chocolate version in quite some time but I think I just melted chips with a little butter for that glaze.