Step 1

Line a baking sheet (or two) with parchment paper.

Step 2

In the bowl of an electric mixer or in a large bowl with a hand mixer, combine butter and both sugars and cream togeher for 2-3 minutes. Scrape the side of the bowl and add the egg and vanilla. Continue mixing for about 7 minutes.

Step 3

Bring the speed of the mixer to low and add the flour, baking powder, baking soda, and salt. Mix until just combined, taking care not to over-mix.

Step 4

Keeping mixer on low speed, add the Cornflake Crunch and chocolate chips and mix until just combined. Fold in marshmallows.

Step 5

Using a 2-oz cookie or ice cream scoop, scoop about 1/3 cup of dough onto prepared cookie sheet, leaving about 4 inches of space between each scoop. With your palm, pat the tops of the dough flat.

Step 6

Wrap cookie sheet tightly with plastic wrap and place in fridge for at least 2 hours and up to a week.

Step 7

When dough is chilled and ready to be baked, pre-heat oven to 375 degrees. Bake cookies for 9-10 minutes, until the cookies are just beginning to brown. Cool completely on pan before moving to an airtight container.

Step 8

Pre-heat oven to 275 degrees.

Step 9

In a large bowl, using your hands, crunch the cornflakes into small pieces. Combine malted milk powder, sugar, and salt with the cornflakes. Add the butter and toss so the cornflakes are coated. Small clusters will form.

Step 10

Spread the cornflake clusters on a baking sheet lined with parchment paper and bake for about 20 minutes until they are getting crunchy. Let cool completely before using in the cookies. This can also be made ahead of time and stored in an airtight container. You will have leftover Cornflake Crunch if making one batch of the Milk Bar cookies.