Step 1

Preheat oven to 375 F. Line baking sheets with parchment paper or silicone baking mat.

Step 2

Melt butter in a heavy saucepan. The butter should be just melted. If you want to brown the butter, please see the note below.

Step 3

Add brown sugar to a large bowl.

Step 4

Pour melted butter over sugar.

Step 5

Stir to combine butter and sugar. Let stand 5 minutes.

Step 6

Add egg and egg yolk; stir to combine.

Step 7

Stir in vanilla extract.

Step 8

Add flour, baking soda, and salt. Stir until just combined. Please see the comments about flour in the recipe notes.

Step 9

Stir in chocolate chips.

Step 10

Using a medium cookie scoop (1.5 tablespoon), drop scoops of dough 2 inches apart on prepared cookie sheet.

Step 11

Bake for about 7-10 minutes, or until the edges of the cookies are golden brown. The centers should still look soft and slightly underbaked. That will help to keep the cookies soft.

Step 12

Let cool on cookie sheet for 5 minutes. Remove to wire rack to finish cooling.