Salted-Toffee Chocolate Chip Cookies

Ingredients

1-3/4 cup unbleached all-purpose flour (8.75 ounces)
1/2 teaspoon teaspoon baking soda
14 tablespoons unsalted butter (1 3/4 sticks)
1/2 cup cup granulated sugar (3 1/2 ounces)
3/4 cups lightly packed dark brown sugar (5 1/4 ounces)
1 teaspoon table salt
2 teaspoons vanilla extract
1 Large whole egg
1 Large egg yolk
1-1/4 cup semisweet chocolate chips or chunks
3/4 cups chopped pecans or walnuts, toasted (optional)

Directions

Step 1	(For High-Altitude: Subtract 1/4 cup of white sugar and subtract 1/4 teaspoon of baking soda). Adjust oven rack to middle position and heat oven to 375 degrees. Line baking sheets with parchment paper. Whisk flour and baking soda together in medium bowl; set aside.
Step 2	Heat 10 tablespoons of butter in a skillet over medium-high heat until melted, about 2 minutes. Continue cooking, swirling pan constantly until butter is dark golden brown and has nutty aroma, 1 to 3 minutes.
Step 3	Remove butter from heat pour browned butter to large heatproof bowl. Stir remaining 4 tablespoons butter into hot butter until completely melted.
Step 4	Add both sugars, salt, and vanilla to bowl with butter and whisk until fully incorporated. Add egg and yolk and whisk until mixture is smooth with no sugar lumps remaining, about 30 seconds. THIS STEP IS KEY: Let mixture stand 3 minutes, then whisk for 30 seconds. Repeat process of resting and whisking 2 more times until mixture is thick, smooth, and shiny.
Step 5	Using rubber spatula or wooden spoon, stir in flour mixture until just combined, about 1 minute. Stir in chocolate chips and nuts (if using), giving dough final stir to ensure no flour pockets remain.
Step 6	Scoop dough into about 3 tablespoons (or use #24 cookie scoop). Arrange 2 inches apart on prepared baking sheets, 8 dough balls per sheet. I separated each dough ball into two parts and shaped into hearts. The dough will still spread into a round shape that somewhat looks like a heart, so you will need to shape the baked cookie into a heart immediately when it comes out of the oven. I used two spatula's to squeeze the bottom of the cookie into a point and pushed the heart crescent shape with the back of a spoon.
Step 7	Bake cookies 1 tray at a time until cookies are golden brown and still puffy, and edges have begun to set but centers are still soft, 10 to 14 minutes, rotating baking sheet halfway through baking. Transfer baking sheet to wire rack; cool cookies completely before serving. Makes 18 cookies.