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Cornflake Marshmallow Chocolate Chip Cookies

These Cornflake Marshmallow Chocolate Chip Cookies are loosely based on Christina Tosi's famous cookie with simplifications and improvements! I love the flavor combination of these cookies made famous by Milk Bar's Christina Tosi - but the cookie recipe is notoriously finicky. I've tested and retested and simplified the recipe to make it easy for you to make! The chunks of sweetened cornflake clusters, the gooey marshmallow center, and the chocolate chips will be your new favorite flavor combination!
Yields 30-36 large cookies. (Dough can be stored in freezer for future use.)
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Author Shannon Lyon | Plum Street Collective

Ingredients

Cornflake Crunch (can make ahead of time)

  • 6 cups cornflakes cereal
  • 1/2 cup malted milk powder (I used the Carnation brand)
  • 1/3 cup white sugar
  • 3/4 teaspoon salt
  • 8 tablespoons unsalted butter, melted

Chocolate Chip Cookie Dough

  • 1½ cups unsalted butter, softened (3 sticks)
  • 1½ cups brown sugar
  • 1 cup white sugar
  • 3 eggs
  • 2 teaspoons vanilla extract
  • 4 cups white flour
  • 1½ teaspoons salt
  • 1½ teaspoons baking soda
  • 3 cups chocolate chips (for this recipe I use semisweet, to offset the sweetness of the marshmallow)
  • 1 bag (10 oz.) mini marshmallows

Instructions

Cornflake Crunch

  • This takes 25-30 minutes to make. If you will have limited time when prepping your cookies, you can make this cornflake crunch up to 3 days ahead of time and store it in an airtight container or ziploc bag so it's ready to use when you make the cookies.
  • To begin, preheat your oven to 250℉. Line a large rimmed baking sheet with parchment paper. Set aside.
  • Next, measure out your cornflakes and add them to a large mixing bowl.
  • On top of the cornflakes, add the sugar, malt powder, and salt. Mix well with two large spoons to combine.
  • Once combined, slowly pour melted butter evenly over the mixture and toss well with two spoons to combine.
  • Pour cornflake mixture out onto the parchment-lined baking sheet, and bake in preheated oven for 20 minutes.
  • Once baked, remove from oven and let cool on the pan for 20 minutes before mixing into the cookie dough. If it's too hot in the dough it can melt the chocolate chips.
    (Alternately you can let cool and then store in an airtight container until ready to make the dough.)

Making the Cookies

  • When ready to make the cookie dough, cream the butter and sugars in a stand mixer for 2-3 minutes, until light and fluffy looking.
  • Add eggs and vanilla and beat for 1 more minute.
  • In a separate bowl, combine flour, salt, and baking soda.
  • Slowly add dry mixture to wet mixture and cream. Then add the chocolate chips and mix on low until incorporated.
  • Next, add in the cornflake crunch mixture and mix on low speed. A lot of the cornflake pieces will break, but that's okay. They taste delicious crumbled up in the cookie dough.
  • If the stand mixer has a hard time incorporating all the cornflakes, you can remove the mixing attachment and finish mixing with a large wooden spoon.
  • Once dough is mixed, scoop large spoonfuls (a cookie scoop helps) of dough onto a parchment-lined baking sheet. For large cookies make the dough size about 1/4-1/3 cup.
  • Once dough is scooped, use the palm of your hand or the back of a spatula to flatten each dough ball.
  • Place 3-4 mini marshmallows in the middle of each flattened dough ball, then fold the dough around the marshmallows and form the dough back into a ball (with the marshmallows at the center).
  • Once marshmallows are in the center of each dough ball, you need to freeze the dough until solid. This will take at minimum 25 minutes (but you can also freeze overnight or longer, if stored in an airtight container or ziploc bag).
  • Once the dough is frozen solid, you are ready to bake these.
  • Preheat the oven to 350°F. Once preheated, place frozen cookie dough balls on a parchment-lined baking sheet, about 2-3 inches apart from each other, so they have room to spread.
  • Bake for 13-16 minutes until tops are set and edges are slightly golden. When you remove from oven, there still should be a slight hump in the center of the cookie.
  • Once they are done baking, let rest/finish baking on the cookie sheet for about 15 minutes, to set.
  • Serve warm or at room temperature. Enjoy!