0 Preheat oven to 350°F and line 2 baking sheets with parchment paper.
1 Place the mini chocolate snowballs into a zip-top bag and use the bottom of a glass or measuring cup to crush them into pieces. Set aside.
2 In the bowl of a stand mixer fitted with a paddle attachment, cream the butter, brown sugar, and granulated sugar until fluffy and light in color, about 2-3 minutes. Scrape the bowl well, then with the mixer on low speed, add the egg and vanilla. Mix until well combined.
3 Scrape the bowl again and add the flour, cornstarch, baking soda and powder, salt, and oats. Mix just until the ingredients are combined. Stir in the crushed chocolate snowballs, reserving a few Tablespoons for the tops of the cookies.
4 Portion the dough using a #24 cookie scoop (about 3 Tablespoons). Place the cookies onto the prepared pans, spacing them at least 2 inches apart. Press the reserved chocolate snowball piecess into the tops of the scoops of dough.
5 Bake at 350°F for 10-12 minutes or until the edges are set and lightly golden brown. Allow to cool for at least 10 minutes and enjoy!
