Prepare 2- or 3-ounce plastic dessert cups by placing on a tray, plate, or muffin pan. You’ll need 16 of the 3-ounce size, or about 20 of the 2-ounce size.

Bring 1 cup of water to a boil on the stovetop or microwave.

In a small bowl, dissolve the blue Jell-O in the boiling water. Once the Jello is fully dissolved, add ¾ cup vodka and stir gently to mix.

Allow the blue mixture to cool a little, then pour it into the shot glasses, filling them about ⅓ with the liquid.

Place the tray of glasses in the fridge for at least an hour. The blue layer will be firm.

Place a layer of Cool Whip on top of the blue layer in each cup. You can either use a small spoon or a pastry bag fitted with a large tip to make an even layer. Place the cups back in the fridge while you prepare the red layer.

Bring 1 cup of water to a boil on the stovetop or microwave.

In a small bowl, dissolve the red Jell-O in the boiling water. Once the Jell-O is fully dissolved, add ¾ cup vodka and stir gently to mix.

Let the red mixture sit at room temperature for 30 minutes to cool down. If you have an instant read thermometer, use it to monitor the temperature until the liquid cools to 80F.

Gently pour the red liquid into each cup, over the Cool Whip.

Place the tray of glasses back in the fridge to set, for at least an hour.