Cream together butter, sugars and peanut butter.
Add eggs and vanilla, mix.
Add flour, baking soda, salt and milk, mix.
Roll dough into balls.
Roll balls into granulated sugar.
Place on ungreased cookie sheet.
Bake at 350 F for 8 minutes until puffed up and balls are slightly cracked.
Pull out of oven, place kiss in center, push slightly down.
Bake another 2 minutes.