Start by pouring 1 ½ cups of cornstarch into a large mixing bowl. You can add up to 2 cups later if needed, depending on the consistency.
Slowly add 1 cup of water to the bowl with the cornstarch, mixing as you go. Add a few drops of food coloring. Stir until the color is evenly blended.
If the mixture feels too runny, sprinkle in a bit more cornstarch and mix again. If it feels too thick and hard to mix, add a tiny splash of water until it has the right texture—firm when squeezed but runny when you release pressure.
Once you have the right consistency, sprinkle in as much glitter as you like. Start with a tablespoon and mix it in, then add more if you want extra sparkle.
Use your hands to mix the glitter evenly throughout the oobleck. Once it’s ready, enjoy the sensory fun of squeezing, poking, and playing with your sparkling oobleck!
Play on a tray or spread a plastic tablecloth to contain the mess. Oobleck can be tossed in the trash when you’re done—just avoid pouring it down the drain.