Line baking sheet with parchment paper.
Preheat oven to 350.
Cream together butter and sugar until fluffy.
Gradually add in the flour and salt.
Add the vanilla and milk and mix until blended.
Roll out dough to 1/4" thick and cut about 2" round cookies.
Place on prepared sheet.
Bake for 12-15 minutes, until the cookies are lightly browned.
Leave on the baking sheet for 2-3 minutes before transferring to cooling rack.
Mix together the peanut butter and powdered sugar.
Line baking sheet with parchment paper.
Spread the mixture on top of each cookie and place in freezer for 10 minutes.
Melt chocolate by microwaveing 45 seconds, stirring and repeating until melted and smooth,
Dip cookies in the chocolate and lift out with a fork shaking off excess.
Place the cookies on prepared sheet and allow to set.