First, over medium-low heat, melt the butter in a medium saucepan (a light-colored pan works best so you can see the color of the butter changing).
Next, melt the butter and cook, swirling occasionally, until it turns a lemony-yellow color, then golden, and finally amber. Remove it from the heat as soon as it turns amber and you see little flecks of brown on the bottom of the pan. Allow it to cool for 30 minutes.
Once cooled, combine butter, brown sugar, and white sugar in a large bowl using a spatula for about 3 minutes.
Then, add the vanilla and eggs and mix until well combined, about 1 minute. After that, add the flour and baking soda until they're fully incorporated.
Fold in the chocolate chunks and the white chocolate chips.
Chill the cookie dough in the fridge for 30 minutes before baking.
Scoop dough into 1" balls (1.5-2 tablespoons) and space 2 inches apart. Sprinkle some flaky salt on top.
Finally, bake the cookies in a preheated oven at 350 degrees F for 10-12 minutes. Let them cool down in the baking tray for 10 minutes before serving them.
Enjoy with a glass of milk!