Pre heat the oven to 160 degrees C.
Line two baking trays with parchment paper.
Mix all purpose flour, baking soda and salt in a bowl.
Whisk butter and sugar for 3-4 minutes with your electric beater on medium speed.
Add egg and egg yolk and mix well.
Add vanilla extract and mix.
Add the dry ingredients and mix till just combined. ( Do not over mix )
Fold in the chocolate chips.
Drop small lemon size balls on the cookie sheet using a cookie scoop or a spoon leaving 2 inch space between each scoop.
Bake for 15-20 minutes in the middle rack, until the sides are slightly browned.
Remove from oven and cool on the baking sheet for 5 minutes.
Transfer on a cooling rack and cool completely.
Store in an airtight container for 2 days.
These cookies are best eaten the same day.