Cream together butter, peanut butter, sugar, and brown sugar
Blend in flour, soda, and salt.
Add egg, milk, and vanilla. Mix to combine.
Shape rounded teaspoons of dough into balls. Roll in sugar and place on an ungreased cookie sheet. Bake 8 mins at 375 degrees.
Remove from oven and place a solid milk chocolate candy kiss on top of each cookie. Press the dough so that cookies crack around edges.
Return cookies to the oven and bake 2-5 minutes longer. Do not overbake. You want the cookies to be lightly browned on the bottom.