Melt the butter in a medium saucepan over medium-low heat. Continue cooking, stirring frequently, for 3-5 minutes, until the butter bubbles, foams and the milk solids start to separate. When the foam subsides, the solids will start to smell nutty and turn a deep amber color. Remove it immediately from the heat and pour it into a medium bowl to cool slightly. Don’t forget all of the brown bits in the pan!
While it's cooling, whisk together the flour, baking soda, and salt in a separate medium bowl.
Add the brown sugar and granulated sugar to the brown butter and whisk to combine. Whisk in the eggs, milk, and vanilla until no yellow streaks remain.
Stir the dry ingredients into the wet ingredients with a rubber spatula. Add the chocolate chunks and stir to combine. Cover with plastic wrap and chill for at least 3 hours, or up to 3 days.
Preheat the oven to 350°F. Line a large baking sheet with parchment paper. Let the cookie dough sit out at room temperature for 30 minutes if it was chilling longer than 24 hours so it's easier to scoop and handle.
Use a large cookie scoop or 1/4 cup measuring cup to scoop the dough. Roll them into balls that are a little bit taller than the standard round balls (see blog post image).
Drop the cookie dough balls on the prepared baking sheet a few inches apart. Bake for 11-13 minutes, or until the edges are golden brown and the top is just set. Let them cool for a few minutes on the cookie sheet then transfer them to a wire rack to cool completely.