- Over medium heat, combine the cornstarch, sugar, and water in a saucepan, stirring continuously.
- Once the mixture begins to thicken, remove the pan from the heat and stir for another minute or so until it thickens to a pudding like consistency. Let it cool for 30 minutes.
- Spoon the mixture into two bowls, stir a few drops of food coloring into each (we used red and yellow), then divide the colors between the ziplock bags. Seal the bags with duct tape and let your child mix and mash the colors (they’ll keep for up to a week).