Good: Powdered Milk.

I had no idea how useful this stuff was until I spent two weeks alone, living off kitchen cupboard detritus. Powdered milk is great! It's like regular milk, but without any liquid in it! You can use it in recipes just like milk, but without adding any fluid!

Yeah, those two weeks were mostly cooking experiments. My grandfather was a baker, I like to think I inherited just a little of his love for food. Apparently I can just slop ingredients together and whatever comes out is usually edible. Go figure.