In a large bowl, mix the melted butter (it needs to be cooled to room temperature to prevent spreading), brown sugar, sugar, vanilla, and eggs. Whisk until smooth.
1 cup Unsalted butter, 1 cup Brown sugar, ½ cup White granulated sugar, 2 teaspoon Pure vanilla extract, 2 Large eggs
Add the all-purpose flour, baking soda, baking powder, cornstarch, and salt. Use a rubber spatula to mix these until just combined.
2 ½ cups All-purpose flour, 1 teaspoon Cornstarch, ½ teaspoon Baking powder, ½ teaspoon Baking soda, 1 teaspoon Salt
Add both chocolate chips and mix. Preheat the oven to 350°F. Line two cookie sheets with parchment paper. Let the dough sit while the oven is preheating before scooping.
1 cup Semi-sweet chocolate chips, 1 cup Dark chocolate chips
Use a large cookie scoop (3 Tablespoons). Scoop 6 cookie dough balls per cookie sheet. Top the cookie doughs with extra chocolate chips.
Bake one cookie sheet at a time. Bake for 13-15 minutes until the edges are golden brown and the middle is slightly underdone. Top the cookies with extra chocolate chips and flaky sea salt *optional.
Let the cookies sit on the hot pan for 5 minutes before transferring to a cooling rack.