Make the brown butter. This whole recipe can be made in the sauce pan that you brown the butter in. So start with a sauce pan large enough to mix all your ingredients. Place 2 sticks or 1/2 cup salted butter in a sauce pan over medium low heat. Gently swirl the butter every so often. Don’t leave the kitchen or stove top while this is happening. I will generally take this time to clean up the dishes or prep other ingredients. When you are getting close, the butter will foam as the water evaporates and you will smell a delicious intense butter smell. Like a really good grilled cheese sandwich. Often when I am making brown butter, my son will ask where is the grilled cheese? So I know the butter is ready:). Keep swirling the pan and as you see the milk solids are browned, remove from heat and allow to cool for about 10 minutes.
Add the sugars to the pan with the brown butter and whisk for 2-3 minutes. Then add the vanilla and eggs and whisk again for 2-3 minutes. The mixture will be thick, glossy and lighter in color.
Add the flour, oats, and baking powder and mix just till combined. Then add in the chocolate chunks and chips. Fold all the ingredients together. Then place the cover on the pan and place in the fridge for 1 hour or overnight. Don’t skip this step.
Preheat the oven to 350 F. I like to use a 1.5 inch scooper to portion out the dough onto a lined sheet tray. This makes about 24 cookies. Space the dough about 2 inches apart.
Bake for 12 minutes. Then allow to cool on the tray for a few minutes before transferring to a cooling rack or plate. Optional to sprinkle with flaky salt after removing from the oven.
