Brown the butter in a stainless steel saucepan according to instructions in another resource. Let it cool after done browning.

Combine flour, baking soda and salt in a medium bowl and whisk well to blend evenly.

In a large bowl, combine cooled brown butter with both sugars and mix gently with a spatula.

Add the egg, milk and vanilla and mix until well incorporated.

Add flour mixture and fold it in. Then add the chocolate chunks and chips before the flour is fully incorporated and mix.

Cover the bowl and refrigerate the dough for 1-4 hours, ideally for 2 hours.

Preheat oven to 375°F and line cookie sheets with parchment paper.

Use a cookie scoop to portion dough into 14 pieces and roll into balls. Place on sheet 3 inches apart.

Bake for 8-10 minutes until golden on top and soft in the middle. Let cool on sheet for 2 minutes before transferring to a wire rack.

Optionally, top with flaky sea salt before serving.