Prep time 10 minutes
Cook time 20 minutes
Preheat oven to 325F (160C) and Line cookie sheets with parchment paper.
With a mixer, mix butter, both sugars and salt. Whip in the egg, yolk and vanilla. Gently mix in flour and soda (do not overmix). Add chocolate chips.
Using a 2 inch spring loaded ice cream scoop, scoop cookie dough onto sheets, placing at least 2 inches apart (cookies spread considerably). Bake for 15-18 min.
They should still be very soft in the center. Do not over bake as the cookies will be crispy rather than soft. Cool on rack.