1) Preheat oven 350* (the cookie dough does need to chill for at least 2 hours first though)
2) Cream together the butter, white and brown sugars until smooth.
3) Add in eggs, egg yolk, and vanilla and mix until fluffy.
4) Stir in Peanut Butter
5) In a separate bowl sift together the flour, baking soda and salt and gradually add into the peanut butter mixture.
6) Refrigerate the dough for at least two hours.
7) Scoop out a spoonful of dough, press it flat and place a mini snickers in the center.
8) Roll into a ball shape making sure the snickers bar is all covered by the dough.
9) Place on a lightly greased cookie pan.
10) Bake for 12-15 minutes, or until the edges are lightly browned.