1) Combine the flour, baking soda and salt together.
2) Beat the butter, sugar, brown sugar and vanilla in a large bowl.
3) Add the egg yolks one at a time, beating well after each addition.
4) Gradually add the flour mixture to the egg mixture.
5) Add the choco chips.
6) Place the mixture using a rounded tablespoon in an ungreased baking sheet.
7) Bake for 9-12 mins at 190 degrees.