Add in the brown sugar and granulated sugar. Mix until fully combined. Add in the whole egg, egg yolk, and vanilla extract until combined for about 30 seconds
Scoop the dough into balls, I like to use a medium size cookie scoop for about 2 ½ tablespoons of dough per cookie, and place them on a Silpat liner then cover in plastic wrap and chill in the refrigerator for 2 hours