230 grams unsalted butter
110 grams granulated sugar
230 grams dark brown sugar
2 large eggs plus 1 egg yolk, at room temperature
300 grams flour
1/3 teaspoon baking powder
1/2 teaspoon cornstarch
1 teaspoon baking soda
1 teaspoon fine sea salt
350 grams chocolate chips
Brown the butter and set aside to cool.
Add the sugars to the melted butter and stir until combined.
Stir in the eggs and the egg yolk, one at a time. Mix until fully combined.
In a separate bowl, mix flour, baking soda, salt, and baking powder.
Use a spatula and fold in the dry ingredients until combined. Fold in the chocolate chips.
Wrap the cookie dough in plastic wrap and keep it in the fridge for at least 24 hours, the longer the better.
Divide the cookie dough into 40 grams balls. Roll and place on baking sheets with parchment paper. Bake in the middle of the oven at 175 C (350 f) for 14 min or until slightly brown around the edges.