Instructions

1. Place half the butter (8 tablespoons) in a medium skillet. Melt the butter over medium heat, swirling it in the pan occasionally. It’ll foam and froth as it cooks, and start to crackle and pop. Once the crackling stops, add in the milk powder, and then keep a close eye on the melted butter, continuing to swirl the pan often. The butter will start to smell nutty, and brown bits will form in the bottom. Once the bits (both the butter solids and milk powder) are amber brown (about 2 1/2 to 3 minutes or so after the sizzling stops), remove the butter from the burner and immediately pour it into a small bowl, bits and all. This will stop the butter from cooking and burning. Allow it to cool until absolutely room temperature. Speed this step up in the refrigerator, but don’t ignore this step.
2. In a medium bowl combine softened butter, room temperature browned butter, brown sugar, and granulated sugar. Using an electric hand mixer, beat on medium speed until well incorporated, lightened in color, and fluffy – 3 to 5 minutes.
3. Add the egg and yolk plus the vanilla extract and beat on low speed for 1 minute, until well incorporated.
4. In a medium bowl whisk together the flour, baking soda, and salt to incorporate the leavening evenly through the flour.
5. Add the dry ingredients all at once to the butter and sugar mixture and beat on low speed or incorporate with a wooden spoon or spatula until no dry patches remain. Stir in the chocolate chips.
6. I find it easier to portion out the cookies before refrigerating them, so roll dough into ~2 1/2 tablespoon balls, and store either in a Tupperware separated by parchment, or place them on a baking sheet and cover them with plastic wrap. Refrigerate for one hour, or overnight. Or until you’re ready to bake them.
7. Line two baking sheets with parchment paper. Place a rack in the upper third of the oven and preheat oven to 350 degrees F. Place dough balls about 2 inches apart on the prepared baking sheet.
8. Bake one cookie sheet at a time for 12 to 15 minutes, rotating the pan halfway through baking.
9. Allow to cool on the pan for 10 minutes before transferring to a wire to cool further before storing.
10. Store in an airtight container at room temperature for as long as they last.