Adding pudding to cake mix

Ok, so most of the time we all like to bake from scratch, but sometimes that isn't feasible. In which case, a doctored cake mix can be fun.

I received this recipe from JanH in the USA, and have had a lot of fun, changing the pudding (instant pudding dry mix) in the recipe for different flavours.

Ingredients
1 box of cake mix (Betty Crocker or similar)
4 whole eggs
1/3 c. water
2/3 c. of buttermilk --full fat. If you use the low fat buttermilk, use 1 c. of low fat buttermilk and omit the water (if you do not have access to buttermilk, use 2 tbsp of vinegar in regular milk, wait 5 minutes for it to curdle)1/3 c. of oil
1 package of instant pudding
For a true white cake, you can just use 6 egg whites (and not whole eggs), but I find the cake sturdier using the whole eggs.

My favourite lately has been to add pistachio instant pudding or cheesecake instant pudding to a vanilla cake mix. The resulting cake is hard to guess has its roots in a packet mix.