Begin by preheating your oven to 375°F (190°C). Line a large baking sheet with parchment paper for easy cleanup and set it aside.
In a mixing bowl, effortlessly combine the cake mix, softened butter, and eggs using a hand-held or stand mixer until they are wonderfully blended.
Next, stir in your peppermint and vanilla extracts. Add green gel food coloring gradually until you achieve a vibrant Grinch green. Mix on low speed just until everything is perfectly combined; the dough will be lovely and thick.
In a small, separate bowl, whisk together the powdered sugar and cornstarch until it’s a light, fluffy mix.
Scoop out about 1.5 tablespoons of the dough for each cookie (a medium cookie scoop works great!). Gently roll each dough ball in the powdered sugar mixture to coat it completely. Place these sweet, coated balls about 1 inch apart on your prepared baking sheet.
Bake for 10 to 12 minutes, or until the edges look set and the tops of the cookies appear dry. Don't overbake to keep them soft!
As soon as you remove the cookies from the oven, immediately press a red heart-shaped sprinkle onto the center of each warm cookie. This helps it stick perfectly!
Let the cookies cool on the baking sheet for about 5 minutes before carefully transferring them to a wire rack to cool down completely. Enjoy your festive, heart-stealing treats!