Preheat your oven to 200°F (93°C) and line two baking sheets with parchment paper.

Beat the egg whites, cream of tartar, and salt in a mixing bowl on medium speed until foamy, about 2-3 minutes.

Gradually add the sugar while beating on high speed for 5-7 minutes until stiff peaks form.

Gently fold in the flavored Jello powder and gel food coloring until fully incorporated.

Transfer the mixture to a piping bag and pipe small swirls onto the prepared baking sheets.

Bake for 1 hour, then turn off the oven and let the cookies cool inside for an additional hour.

Remove from the oven and let sit for a few minutes before transferring to a wire rack to cool completely.