Brown the Butter: Melt 1 cup of unsalted butter in a light-colored saucepan over medium heat, stirring continuously for about 5-7 minutes until golden brown.

Mix Dry Ingredients: In a bowl, whisk 1.75 cups flour, 1 tsp baking soda, 0.5 tsp baking powder, 1 tsp cornstarch, and 0.5 tsp salt; set aside.

Cream Butters & Sugars: In a large bowl, beat the cooled brown butter, 1 cup dark brown sugar, and 0.5 cup granulated sugar for about 3 minutes.

Add Eggs & Vanilla: With the mixer on low, add 2 eggs one at a time and then mix in 2 tsp vanilla extract until well combined.

Combine Mixtures: Gradually add dry ingredients to the wet mixture, folding gently to combine, then fold in chocolate chips.

Chill the Dough: Cover the dough and refrigerate for at least 30 minutes (up to 48 hours for best results).

Bake Cookies: Preheat oven to 350°F (175°C). Scoop dough into tablespoon-sized balls on parchment-lined sheets, leaving space between them.

Bake: Bake for 10-12 minutes until edges are golden brown and centers are soft; cool on the sheet for 5 minutes before transferring to a wire rack.