Preheat oven to 350. Prepare cake mix as directed. Pour batter into 13x9 pan.
Pour milk and water into a large bowl. Add dry pudding mixes and sugar. Beat with wire whisk until well blended. Pour pudding mixture over cake batter. Put the baking dish on a cookie sheet...this bubbles up!!
Bake 55 minutes or until toothpick comes out clean. Cool in pan for 20 min. Sprinkle with powder sugar. Serve warm!! Also can eat cooled...the sauce turns from saucy to custardy like!! YUMMM