PREHEAT oven to 350°F. Mix flour, baking soda and salt; set aside.
BEAT butter with peanut butter until smooth. Gradually add sugar, beating until light and fluffy after each addition. Blend in egg. Add flour mixture alternately with milk, mixing well after each addition. Blend in vanilla.
SHAPE 1 tsp. of dough into ball; flatten with glass. Press about a teaspoonful of cereal into top of each cookie. Place about 2 inches apart on baking sheets which have been sprayed with cooking spray. Repeat with remaining dough and cereal.
BAKE 10 to 12 minutes or until lightly browned. Remove to wire racks; cool.