Combine flour, baking soda and salt, set aside. Using an electric mixer, cream together butter, peanut butter, ½ cup granulated sugar and light brown sugar. Add egg, milk and vanilla; beat until well blended. Gradually add flour mixture, mixing thoroughly.
Preheat oven to 375℉. Spray, grease or line cookie sheets with a non-stick liner and set aside. Roll dough into golf ball sized balls. Roll each into granulated sugar and place on cookie sheets about 2 inches apart.
Bake until very light brown and puffed, about 8 minutes. Remove sheet from oven and lightly press a candy kiss into the center of each cookie, allowing it to crack slightly. Return to oven until light golden brown, 3 minutes. Remove from oven, cool completely and store in airtight container.
Notes
This recipe says it make 5 dozen cookies but they make the cookies much smaller than I do :) I like mine big.