Brown the butter: Add the butter to a saucepan and cook over medium heat. Once melted, it will begin to foam and bubble as the water evaporates. Stir constantly until the milk solids turn light golden brown and the butter smells nutty. Remove from heat immediately and transfer to a bowl. Let it cool slightly. Follow the instructions on how to make brown butter.
Mix butter and sugars: Add the brown sugar and white sugar to the warm brown butter. Whisk until fully combined and glossy. This step helps dissolve the sugars and builds a rich caramel flavor.
Add wet ingredients: Mix in the egg and vanilla extract until smooth and emulsified. If using milk, add it at this stage to replace the moisture lost during browning and keep the cookies soft.
Combine dry ingredients: In a separate bowl, whisk together the flour, baking soda, and salt to ensure even distribution.
Make the dough: Gradually add the dry ingredients to the wet mixture. Mix just until combined and no dry flour remains. Avoid overmixing to keep the cookies tender.
Add chocolate: Fold in the chocolate chips or chunks evenly throughout the dough.
Chill the dough: Cover the dough and refrigerate for 1–2 hours. For deeper flavor and better texture, the dough can be chilled overnight.
Shape the cookies: Scoop equal portions (about 40g per cookie or whatever size you like) of dough and shape into balls. Place them on a lined baking tray, leaving enough space (3 inches apart) for spreading.
Bake: Preheat the oven to 340–350°F (170–175°C ). Bake the cookies on the middle rack until the edges are set and lightly golden while the centers remain soft.
Cool and serve: Allow the cookies to cool on the baking tray for 5–10 minutes before transferring to a wire rack. They will continue to set as they cool while staying soft inside.