Preheat the oven to 350℉. Prep the baking trays by lining them with parchment paper and set aside. Melt the butter in the microwave or using a double boiler method and set aside to cool for at least 10 minutes while you prep the rest of your ingredients.
Into a large bowl, whisk the brown sugar, white sugar, maple syrup, and melted butter.
1/2 cup unsalted butter, 3/4 cups white sugar, 1/4 cup light brown sugar, 2 tbsp maple syrup
Add in egg, milk, and vanilla and continue whisking.
1 large egg, 1 tsp milk, 1 tbsp vanilla
Add in flour, baking soda, baking powder, and salt. Fold until a dough forms. The dough will be loose and resemble a batter more than a cookie dough.
1 1/3 cups all purpose flour, 1/2 teaspoon baking soda, 1/4 teaspoon baking powder, 1/4 teaspoon salt
Mix in both chocolate chips.
1/2 cup semisweet chocolate chips, 1/4 cup mini chocolate chips
Scoop 6 cookie dough balls and place on the prepared cookie sheet at least 3 inches apart from one another. They spread a lot in the oven! Don't worry if the cookies aren't perfectly round when scooping.
Bake for 12-15 minutes. Mine took 14 minutes. The cookies will be ready when the edges are crisp dark brown, and the middle will be a light brown and slightly puffed. Remove from oven and immediately sprinkle flakey sea salt (optional but recommended).
Flakey sea salt
Let the cookies cool on the hot pan for a few minutes before transferring to a rack and enjoy! Cookies taste best and have the best crisp when eaten fresh, but they can be stored in an airtight container from up to 5 days at room temperature.