Engineered Cooking

1. In a small bowl, whisk together the flour, baking powder, and baking soda.

2. Slice 4 tablespoons of the butter into four pieces, and place them in a large bowl. Melt the remaining 8 tablespoons of butter in a medium sauce pan over medium-high heat. Continuously whisk the butter until the butter browns, it will give off a nutty aroma.
Pour the browned butter (and any bits of browned butter stuck to the bottom of the sauce pan) into the bowl with the room-temperature butter, and stir until all the butter
is melted and combined.

3. Stir in the granulated and brown sugars, vanilla, and salt to the butter with a rubber spatula, mixing until combined. Whisk in the egg and the yolk until fully combined, about 45 seconds, until it is smooth and glossy. Let the batter sit for 2 to 3 minutes, and then whisk again for 45 seconds.

4. Pour the flour mixture into the wet ingredients and use the spatula to combine (it may take a minute to incorporate all the dry ingredients). Place the chopped chocolate
over the dough and use your hands to knead it in until it is evenly distributed.

5. Roll the dough into 25-gram balls and add the fleur de sel on top if using. Once all the dough has been rolled out and put onto the sheet pans place in the fridge for a minimum of 2 hours (can be left in the fridge overnight).

6. Adjust the oven rack to the middle of the oven. Preheat the oven to 350°F.

7. Remove the dough from the fridge as needed to fill a baking sheet with 8 cookies at a time, keep the remaining dough in the fridge while the cookies bake. Bake the cookies for 8 - 10 minutes, let cool completely on a wire rack.