Combine butter, sugars, peanut butter, egg and vanilla and beat until fluffy.

Combine flour, baking soda and salt and gradually add to the butter mixture.

Beat until well blended.

Form into 1 inch balls and drop into cups on small muffin pan.

Bake for about 8 to 10 minutes at 350 degrees or until puffy and lightly brown.

Press unwrapped Reese in center or each cookie and allow to cool completely in muffin pan.