- 2 sticks (equals 1 cup or 16 tbsp. or 8 oz.) unsalted butter, room temperature (Must be full fat! Don't try to substitute here)
- 1 1/4 cup granulated sugar
- 2/3 cup light brown sugar, tightly packed
- 1 egg
- 1/2 tsp. vanilla extract
- 1 1/2 cups all purpose flour
- 1/2 tsp. baking powder
- 1/2 tsp. baking soda
- 1 1/2 tsp. kosher salt
- 3 cups Cornflake Crunch
- 2/3 cup mini chocolate chips
- 1 1/4 cup mini marshmallows
- In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and sugars on medium-high speed for 2-3 minutes. Scrape down sides of the bowl with a spatula.
- Add egg and vanilla extract and beat 7-8 minutes.
- On low speed, mix in flour, baking powder, baking soda, and salt until just combined (1 minute max.). Don't step away from the machine/over-mix!
- Scrape down sides and, still on low speed, paddle in the cornflake crunch and chocolate chips until just incorporated (30-45 seconds), then stir in the marshmallows as well.
- Line a cookie sheet with parchment paper. Measure 1/3 cup portions of dough (using a 2 oz. ice cream/cookie scoop) onto the pan. Pat tops of dough mounds flat. Wrap the pan tightly with plastic wrap and refrigerate at least 1 hour and up to 1 week. (Do not bake at room temperature!)