Instructions
Step 1
In a large pot over medium-high heat, melt the butter and cook, using a wooden spoon to stir and scrape the bottom of the pot frequently, until the solids are toasty, browned, and very fragrant, about 8 minutes. (Do not walk away from the stove; butter can go from perfectly browned to burned and bitter very quickly.) Remove from the heat, then immediately stir in the brown sugar. Set aside until room temperature.
Step 2
In a large bowl, whisk together the flour, salt, and baking soda.
Step 3
When the butter-sugar mixture has cooled, use the wooden spoon or a silicone spatula to stir in the eggs and yolks, then stir in the flour mixture until just combined. Cover and refrigerate the dough until firm, at least 4 and up to 24 hours.
Step 4
Position racks in the top and bottom thirds of the oven and preheat to 350°F. Scoop the dough into 32 two-tablespoon portions, then roll each into golf ball-sized spheres. Working in batches, arrange the spheres 3 inches apart on two parchment-lined baking sheets and bake, rotating and swapping the top and bottom pans halfway through cooking, until the cookies have spread and are lightly browned on top and slightly darker at the edges, about 12 minutes. Transfer to a wire rack. Between batches, rinse (under cold water), dry, and reline the baking sheets with parchment. Serve warm or at room temperature, or, if making ice cream sandwiches, chill the cookies before assembling.