Step 1

In a large bowl using a hand-held mixer or stand mixer with paddle attachment, beat the butter for 1 minute on medium speed until completely smooth and creamy. Add the brown sugar and granulated sugar and mix on medium speed until fluffy and light in color. Mix in egg and vanilla. Scrape down the sides and bottom of the bowl as needed. In a separate bowl, combine flour, cornstarch, baking soda and salt. On low speed, slowly mix into the wet ingredients until combined. The cookie dough will be quite thick. Add the chocolate chips, white chocolate chips, and Sno-Caps and mix for about 5 seconds until evenly disbursed. Cover dough tightly with aluminum foil or plastic wrap and chill for at least 1 hour and up to 2 days. Chilling is mandatory for this cookie dough.

Step 2

Remove cookie dough from the refrigerator and allow to sit at room temperature for 10 minutes. Preheat oven to 350°F (177°C). Line a large baking sheet with parchment paper or a silicone baking mat. Set aside.

Step 3

Once chilled, the dough will be slightly crumbly, but will come together if you work the dough with your hands as you roll into individual balls. Roll balls of dough, about 1 Tablespoon of dough each, into balls. Bake for 8-9 minutes, until barely golden brown around the edges. They will look extremely soft when you remove them from the oven. Allow to cool for 5 minutes on the cookie sheet. If the cookies are too puffy, try gently pressing down on them with the back of a spoon. They will slightly deflate as you let them cool. Transfer to cooling rack to cool completely.

Step 4

Cookies stay fresh covered at room temperature for up to 1 week.