From Momofuku Milk Bar
225 g butter, at room temperature (2 sticks)
250 g granulated sugar (1.25 c)
150 g light brown sugar (.66 c tightly packed)
2 g vanilla extract (0.5 tsp)
240 g flour (1.5 c)
2 g baking powder (0.5 tsp)
1.5 g baking soda (0.25 tsp)
5 g kosher salt (1.25 tsp)
270 g Cornflake crunch (3 c/3/4 recipe)
125 g mini chocolate chips (0.66 c)
65 g mini marshmallows (1.25 c)
Combine the butter, sugars and glucose in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2 to 3 minutes. Scrape down the sides of the bowl, add the egg and vanilla, and beat for 7 to 8 minutes.
Reduce speed to low and add the flour, baking soda, baking powder and salt. Mix just until the dough comes together, no longer than 1 minute. (Do not walk away from the machine during this step, or you will risk overmixing the dough.) Scrape down the sides of the bowl with a spatula.
Still on low speed, paddle in the cornflake crunch and mini chocolate chips just until they're incorporated, no more than 30 to 45 seconds. Paddle in the mini marshmallows just until incorporated.
Using a 2 3/4-ounce ice cream scoop (or a 1/3-cup measure), portion out the dough onto a parchment-lined cookie sheet. Pat the tops of the cookie dough domes flat. Wrap the sheet tightly in plastic wrap and refrigerate for at least 1 hour, or up to 1 week. Do not bake the cookies from room temperature - they will not hold their shape.
Heat the oven to 375°F.
Arrange the chilled dough a minimum of 4 inches apart on parchment- or silpat-lined sheet pans. Bake for 18 minutes. The cookies will puff, crackle and spread. After 18 minutes, they should be browned on the edges and just beginning to brown in the center. Give them an extra minute or so if that's not the case.
Cool the cookies completely on the sheet pans before transferring to a plate of an airtight container for storage. At room temp, the cookies will keep fresh for 5 days; in the freezer they will keep for up to a month.