1. Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper or silicone baking mats.

2. In a large mixing bowl, beat the softened butter and 1/2 cup powdered sugar together until light, creamy, and slightly fluffy.

3. Mix in the vanilla extract, peppermint extract, and green gel food coloring (if using) until the color is evenly distributed.

4. In a separate bowl, whisk together the all-purpose flour, cornstarch, and fine sea salt until well combined.

5. Add the dry ingredients to the butter mixture and mix on low speed or with a spatula just until a soft dough forms and no dry streaks remain.

6. Fold in the mini chocolate chips until they are evenly distributed throughout the dough.

7. Scoop about 1 tablespoon of dough per cookie, roll each portion into a smooth ball, and place on the prepared baking sheets about 1 inch apart.

8. Bake for 11 to 13 minutes, or until the bottoms are just lightly golden and the tops look set but still pale. Do not overbake.

9. Let the cookies cool on the baking sheet for 5 minutes, then gently roll each warm cookie in powdered sugar and transfer to a wire rack.

10. Once the cookies are completely cool, roll them in powdered sugar a second time for a thick, snowy coating.