Here's the recipe I use:
1 white cake mix
1 pkg pistachio pudding
3 eggs
1 c oil
1 c 7-up (room temperature)
mix and bake at 350 degrees for 50 minutes in greased, floured bundt pan
1 pkg pistachio pudding
1 envelope Dream Whip
1 1/2 c cold milk
Whip for 5 minutes. You can use the frosting to frost the outside, or cut layers and put it between, or mound it in the middle of the bundt.
Store in refridgerator.
It's been a long time since I've made it and unfortunately the size of pudding box wasn't written in my directions. I'm guessing small?