I am doing a messy session and hoping for a tip on mixing up a bucket of cake batter that is quick

use a cement mixer, and then burn your house down. thats how i always do it.

The simplest answer is usually the most correct.

Bucket, warm water, drill, mixer.

Job jobbed and less expensive than previous suggestion.

Less fun though.

We are the mess-makers, and we are the creamers of creams.

See: my sessions, album.
That is how you mix a big amount fairly quickly. Be sure to have a second battery on hand if you are mixing more than that or are mixing something thicker. When I mix the mystery substance I have to take time to let batteries charge. One bucket will take down a battery bc it is so thick. You can get those mixers for like 7 bucks. I have like, 4 of them. Haha.

Also, see my drill. You need one with lots of power no Itty drill will do