Brown the Butter: In a large saucepan, melt unsalted butter over medium heat until it begins to foam. Stir continuously for about 5-10 minutes, until the milk solids turn amber and release a nutty aroma. Pour the brown butter into a measuring cup and allow it to cool.

Mix Dry Ingredients: In a separate bowl, sift together all-purpose flour, baking soda, salt, and cornstarch.

Combine Ingredients: In a mixing bowl, beat the cooled brown butter with both white and brown sugars until the mixture is light, creamy, and fluffy. Add in the eggs and vanilla extract, mixing until fully combined.

Integrate Dry Ingredients: Gradually add the dry mixture into the wet mixture on low speed, mixing just until combined. Fold in the semi-sweet and mini chocolate chips.

Prep for Baking: Preheat your oven to 350°F (175°C) and line your cookie sheets with parchment paper. Let the dough rest for about 10 minutes.

Scoop and Bake: Use a cookie scoop to portion out the dough, placing six cookies on each baking sheet. Bake for 10-13 minutes, or until the edges are golden brown. Let them cool on the baking sheet for 4 minutes before transferring to a cooling rack.