Cake batter!
My youngest and I made a "tie dye" cake. It came out awesome. Tons of color manipulation fun for kids. And adults.
This was right before baking. 3 dye colors (red, yellow, blue) combine for 6 batter colors. They are just about as bright after baking. Fat bands of each color in the sliced cake.
A lot of small bowls though (6 for each layer, 12 altogether).