Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or lightly grease it.
In a large mixing bowl, combine the cake mix, eggs, vegetable oil, and vanilla extract.
Mix until a soft dough forms. The dough will be slightly sticky.
Gently fold in half of the red and green sprinkles, white chocolate chips, or festive M&M's into the dough.
Scoop tablespoon-sized amounts of dough and roll them into balls.
Place them on the prepared baking sheet about 2 inches apart.
Flatten the dough balls slightly with your palm.
Sprinkle additional red and green sprinkles on top of each cookie for extra holiday cheer.
Bake in the preheated oven for 9-11 minutes, or until the edges are set but the centers are still soft.
Avoid overbaking to keep the cookies chewy.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Once cooled, serve your festive cookies on a platter or package them as holiday gifts!