Prepare Dough: In a large mixing bowl, combine the cake mix, vegetable oil, eggs, and vanilla extract. Mix until smooth. Add green gel food coloring a little at a time until you reach the desired “Grinch green” color.

Chill the Dough: Cover the bowl with plastic wrap and refrigerate the dough for at least 1 hour. This makes the dough easier to handle and prevents spreading during baking.

Preheat Oven: Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

Shape Cookies: Scoop about 1 tablespoon of dough and roll it into a ball. Roll each dough ball in powdered sugar until fully coated. Place the dough balls on the prepared baking sheets, spacing them about 2 inches apart.

Bake: Bake in the preheated oven for 10-12 minutes, or until the cookies are set and the edges are firm. The cookies will crinkle as they bake.

Add Hearts: If using heart-shaped sprinkles, gently press one into the top of each cookie immediately after removing them from the oven.

Cool: Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.