For the cornflake chocolate chip marshmallow cookies:
1cup (2 sticks; 226 grams)unsalted butter,at room temperature (around 70°F)
1cup (200 grams)light brown sugar,packed
½cup (100 grams)granulated sugar
1large egg
½teaspoonvanilla extract
2cups (250 grams)bread flour(I use King Arthur Baking brand)
½ teaspoonbaking powder
½teaspoonbaking soda
1 ¼teaspoon (6 grams)Kosher salt
3cups (270 grams)cornflake crunch recipe(about ¾ of the recipe)
⅔cup (125 grams)mini chocolate chips
1 ¼cups (65 grams)mini marshmallows(I use Kraft/Jet Puffed brand)
Instructions
Do not pass Go until you've read the tips above
Before you start, I recommend you read the tips listed above in my blog post before proceeding. Every little step counts to ensure the perfect cornflake chocolate chip marshmallow cookie outcome.
Make the cornflake crunch:
Preheat the oven to 275°F.
In a medium bowl, crush the cornflakes with your hands until they are about one-quarter their original size. Add the milk powder, sugar, and salt and mix to combine. Set aside.
In a heavy-bottom skillet or saucepan, melt the cubed butter on medium heat, whisking frequently. Don’t be worried if the butter starts to foam up and get bubbly. It will subside. Watching carefully, cook until the butter has browned and you see brown specs and smell a nutty aroma. Remove from the heat and immediately pour into the cornflake mixture. Toss all the ingredients together and mix to combine with a rubber spatula.
Pour the cornflake mixture onto a sheet pan lined with parchment paper and bake for 20-25 minutes until toasty.
Let the cornflake crunch cool completely before using. If not using right away, you can store it in an airtight container at room temperature for a few days.
Make the cookie dough:
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugars together on medium-high for 3 minutes. Stop the mixer, scrape down the paddle, the bottom, and sides of the bowl. Add the egg and vanilla and beat for another 7 to 8 minutes on medium-high speed. Yes, the full 7-8 minutes and not 1 minute shorter; making it a total of 10 minutes (see notes above). At this point, the butter should be light and fluffy and pale in color.
In the meantime, mix to combine the flour, baking powder, baking soda, and salt. Once you have creamed the butter for 10 minutes, add the flour and mix on low until about 90% incorporated. This should only take a few seconds. Remember, we do not want to overmix the dough. It’s okay if it’s not fully incorporated because we will mix one more time.
Scrape down the bowl again. Then add the cornflake crunch and mini chocolate chips (and the marshmallows if you prefer to strategically scoop the cookie dough balls rather than manually stuffing the marshmallows into the dough). On low speed, mix just until incorporated, about 15-30 seconds.
Portion, chill, and rest the cookie dough:
Using a 1-ounce cookie scoop, portion the cookie dough into balls and place onto a parchment paper-lined sheet pan. Remember, it’s important to be mindful of the placement of the marshmallows. We want to avoid having any fully exposed marshmallows on the bottom or lower sides of the cookie dough ball otherwise they will burn during baking. If you mixed the marshmallows into the cookie dough along with the cornflake crunch and chocolate chips, then just be sure to scoop the marshmallow pieces first and press the marshmallows into the center if needed. Alternatively, if you didn’t add the marshmallows directly into the cookie dough, place 2 marshmallows into the cookie scoop first, then scoop some dough (about ⅓ of the scoop), add 2-3 marshmallows, and then scoop the remaining dough. It’s okay if the marshmallows are peeking out on the top or upper sides of the dough ball. We just want to avoid the lower sides and bottoms of the cookies.
Arrange the cookie dough balls on a parchment paper-lined baking sheet and wrap the cookie dough with plastic wrap and refrigerate for at least 2 hours up to 3 days. For best results, let the cookies chill and rest for at least 24 hours to help develop a deeper flavor and better texture. I know, I know. Waiting is the worst but it’s worth it. You can also freeze the cookie dough balls.
Bake the cookies:
Preheat the oven to 350°F.
Arrange the cookies on a parchment paper-lined baking sheet leaving space between. At this point, I like to top the cookie dough balls with a marshmallow by gently pushing it onto the top of the dough ball until it sticks. It may deflate the marshmallow but that’s okay as long as it sticks to the top. This will ensure you get that Instagram-worthy toasty marshmallow on top.
Bake for 11-13 minutes. Shape into round cookies (see note below or tips above).
Let cookies cool on the sheet pans on a wire cooling rack. Do not fuss with them for at least 5 minutes or they might crumble if you try to loosen them right away. Once cooled, gently loosen the bottoms using a spatula. Enjoy!
Notes
How to get perfectly round cookies:As soon as you take the cookies out of the oven (you must do it while they’re still hot and pliable), use a biscuit cutter, ring mold, or cup that is wider than the cookie to shape them into a round circle. Do so by placing the biscuit cutter around the cookie and then gently moving it in a circular motion around the edges of the cookie to shape it into a perfect circle. It’s okay if the bottoms are stuck. Just carefully shape the edges. We will loosen the cookies from the parchment paper once they’ve cooled. This step is not necessary, but makes for a picture-perfect cookie.Can I freeze these? Yes, absolutely. You can freeze the portioned cookie dough balls and then bake straight from frozen. They may just need a few extra minutes to bake.Can I bake on a Silpat or silicone baking mat? I recommend baking on parchment paper only in order to prevent spreading.
Course: Dessert, Snack
Cuisine: American
Keyword: Christina Tosi, Cornflake chocolate chip marshmallow cookies, Cornflake cookies, Cornflake crunch, Cornflake crunch cookies, Milk Bar, Milk Bar cookies, Milk Bary NYC, Momofuku Milk Bar