Preheat oven to 375 degrees. Line baking sheets with parchment paper or silicone baking mat.In a large bowl, combine melted butter and brown sugar. Let stand 5 minutes.

Add in the egg and egg yolk; stir to combine.

Stir in vanilla extract. Add flour, baking soda, and salt. Stir until just combined.

Stir in chocolate chips.

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

Bake at 375 for 7-10 minutes, or until the edges of the cookies are golden brown.

Allow to cool on cookie sheet for 5 minutes. Remove to wire rack to finish cooling. Makes 3 dozen cookies.