Chewy Brown Butter S'mores Cookie

Add butter to a small saucepan over medium heat. Cook, stirring frequently, until the butter foams and golden brown bits form on the bottom of the pan. The butter should began to boil rapidly, smell nutty and fragrant. Once the rapid bubbling stops and it gets quiet the butter should be a nice amber color. Remove the butter from heat and pour into a large bowl If using milk powder, whisk it into the hot butter immediately and allow the brown butter to cool for 10 to 15 minutes, till the butter is cool to touch.

Add brown sugar and granulated sugar to the cooled butter mixture and whisk until smooth. Whisk in the egg and vanilla extract until glossy.

In a separate medium bowl, whisk together, flour, graham cracker crumbs, cornstarch, baking soda and salt. Add the flour mixture to the wet ingredients and mix just until just a few visible dry streaks remain. Add in the chopped milk chocolate and mix just till evenly disturbed.

Using a large cookie scoop, divide the dough into approximately 9 cookie dough balls (about 3 ounces each). Place dough onto a parchment paper-lined prepared baking sheet, leaving plenty of space between each cookie, about 5 inches. Chill the dough for about 15 to 20 minutes while the oven preheats at 350°F.

Bake at 350°F (177°C) for 8 minutes. Remove cookie sheet, while the cookies are still on the tray and firmly tap the cookie sheet on the oven rack or countertop to encourage the cookies to spread. You want to tap the tray at least three times and then gently place three marshmallow halves on top of each cookie, preferably in the center of the cookie so it doesn't melt off. Return cookies back in the oven for another 4 to 5 minutes, or until the marshmallows are soft and beginning to toast, the cookie center is slightly puffed and the edges are golden brown. If desired, lightly toast the marshmallows with a kitchen torch after baking. Immediately use a round cookie cutter slightly larger than the cookies or another round object to gently swirl each cookie into a perfectly round shape. Sprinkle with flaky sea salt if desired. Allow the baked cookies to cool on the baking sheet for 10 minutes before transferring to a wire rack to completely cool.