Brown the Butter:

1. Using 1 cup of butter (237g/2 sticks), slice the each stick of butter into 8 thin slices. Save the remaining 2 Tbsp (about 30g), at room temperature, for the mixer.
2. In a light-bottomed saute pan or saucepan, placed over Medium-Low heat, place the sliced butter. Stir or whisk the butter while it melts and continue slowly stirring/whisking as it cooks. It will begin to spatter, then after a bit it will foam. After several minutes of foaming, the milk solids will separate and move to the bottom of the pan. Ultimately (after a total of 4-9 minutes after the butter hit the hot pan) the solids will begin to brown and the liquid part will turn golden. Watch closely to make sure it does not burn. Once the milk solids turn brown, remove the brown butter from the heat. It will continue cooking until you pour it into a heat-proof container to cool to room temperature. If making the day before you make the cookies, once it comes to room temperature, cover and place in the refrigerator, removing at least 30 minutes before you make the cookie dough.

Make the Cookie Dough:

1. In a medium bowl, whisk together the AP flour, wheat flour, milk powder, baking powder, baking soda and salt. Set aside.
2. Make sure the brown butter is slightly soft, (not melted) – you may need to microwave it on the defrost setting for 15 or 30 seconds. Add it (include all of the browned bits!) to the bowl of a stand mixer, or a bowl in which you can use a hand mixer, along with the remaining 2 Tbsp (30g) ROOM TEMPERATURE OR SLIGHTLY SOFTENED unbrowned butter. Mix on low, moving up to medium as you are able, for about a minute.
3. Add the brown sugar and white sugar, and beat at Medium speed for 4-5 minutes until the mixture is light and fluffy. One at a time, add the eggs, making sure the first is fully incorporated before adding the second.
4. Turn the speed down to low (1-2), and gradually add the flour mixture, mixing until it is just incorporated. Add the vanilla and the oats, and mix just to combine. 
5. Using a stiff spatula or large spoon, mix in the shaved/chopped chocolate until evenly distributed.

Scoop and Refigerate the Dough:

1. Onto a parchment-or-buttered sheetpan, using a level large (3 Tbsp) medium (2 Tbsp) heaping Scoop, add scoops of dough to the pan, using all of the dough. You should be able to make 29 scoops. Cover with plastic wrap and store the scoops in the refrigerator for 18-24 hours (or longer if you’re patient enough – up to 72 hours).

Bake

1. Preheat oven to 350F (Conventional) or 335F (Convection/Fan).
2. Transfer refrigerated scoops to a parchment or butter-coated sheetpan, leaving 3 inches between scoops. You should be able to place 7-8 scoops per pan.
3. Bake 2 sheets at a time, rotating halfway through baking to ensure uniform baking. Once the edges are light golden brown, (likely between 11 and 13 minutes – mine took 12 minutes) remove and cool on sheet pans for 5 minutes before removing to cooling rack. If you want, add some pieces of chocolate or chocolate chips to the warm tops to create a “puddle” effect. Sprinkle, if desired, with just a bit of flaky sea salt.