America's Test Kitchen Brown Butter Chocolate Chip Cookies

 Ingredients:

• 1 ¾ cup (8 ¾ ounces) all–purpose flour
• ½ teaspoon baking soda
• 14 tablespoons unsalted butter
• ¾ cup packed (5 ¼ ounces) dark brown sugar
• ½ cup (3 ½ ounces) granulated sugar
• 2 teaspoons vanilla extract
• 1 teaspoon salt
• 1 large egg plus 1 large yolk
• 1 ¼ cups (7 ½ ounces) semi-sweet chocolate chunks
• ¾ cup slivered almonds 

Steps:

1. Adjust oven rack to middle position and heat oven to 375 degrees. Line 2 baking sheets with parchment paper. Whisk flour and baking soda together in a bowl.
2. Melt 10 tablespoons butter in a 10-inch skillet over medium-high heat. Continue cooking, swirling pan constantly, until butter is dark golden brown and has nutty aroma, 1 to 3 minutes.
3. Transfer browned butter to large bowl and stir in remaining 4 tablespoons butter until melted. Whisk in brown sugar, granulated sugar, vanilla and salt until incorporated. Whisk in egg and yolk until smooth with no lumps, about 30 seconds.
4. Let mixture stand for 3 minutes, then whisk for 30 seconds. Repeat process of resting and whisking 2 more times until mixture is thick, smooth, and shiny. Using rubber spatula, stir in flour mixture until just combined, about 1 minute. Stir in chocolate chips and pecans, if using.
5. Working with 3 tablespoons dough at a time, roll into balls and space 2 inches apart on prepared sheets. (Raw cookies can be frozen for up to 1 month; bake frozen cookies in 300-degree oven for 30-35 minutes.)
6. Bake cookies, 1 sheet at a time, until golden brown and edges have begun to set but centers are still soft and puffy, 10 to 14 minutes, rotating sheet halfway through baking. Let cookies cool completely on sheet and serve.