There are a ton of recipes for puffy paint floating around on the internet. They all vary a little, but this is what we picked:
For each color:
1 Tablespoon Self-Rising Flour
1 Tablespoon Salt
1-2 Tablespoons Water
1-2 drops Food Coloring
Paint on a thick piece of card stock or thin piece of cardboard. We used cardboard, but I think card stock would have worked just as well. Microwave for 30 seconds and watch your paint turn puffy!
This paint is so fun I had to give it a try.