From Martha Stewart show, featuring recipe from Christina Tosi, owner of Momofuku Milk Bar in NYC. This recipe needs "Cornflake Crunch", which is a separate recipe.
Cream together butter adn both sugars in the bowl of electric mixer on medium high, 2-3 minutes. Scrape down sides of bowl. Add egg, vanilla. Beat for 7-8 minutes more.
2
Reduce speed to low. Add flour, salt, baking powder, baking soda. Mix just until dough comes together, no longer than 1 minute. Scrape down sides.
3
With the mixer on low, add 3 cups of CORNFLAKE CRUNCH (different recipe), chocolate chips. Mix just until combined. Add mini marshmallows just until incorporated.
4
Line a baking sheet with parchment paper. Using a 2 3/4 ounce ice cream scoop, or 1/3 cup, portion dough onto prepared baking sheet. Pat tops of cookie domes flat. Wrap tightly with plastic wrap and refrigerate for at least 1 hour and up to 1 week. Do not bake cookies at room temperature or they will not hold their shape.
5
Preheat oven to 375 degrees F. Line additional baking sheets with parchment paper or nonstick baking mats.
6
Arrange chilled dough at least 4 inches apart on prepared baking sheets. Transfer to oven and bake until puffed, cracked and spread...browned on the edges, about 16-18 minutes. Let cool completely on baking sheets.
Cookies can be stored in airtight container at room temperature for up to 5 days, and frozen for up to 1 month.