Beat 6 tablespoons butter and 1/2 cup sugar in mixer bowl until well blended. Add corn syrup, egg and vanilla; blend well.
Set aside 1/2 cup peanut butter chips for glaze. Place remaining chips and remaining 2 tablespoons butter in medium-microwave safe bowl. Microwave at MEDIUM (50%) 1 minute; stir. If necessary, microwave at MEDIUM 15 seconds at a time, stirring after each heating, until chips are melted and mixture is smooth when stirred. Blend into butter mixture.
Stir together flour, baking soda and salt; add peanut butter mixture, blending well. Refrigerate 30 minutes or until firm enough to handle.
Remove wrappers from peanut butter cups. Heat oven to 350°F. Shape dough into 42 balls (about 1 inch each); roll in sugar. Place on ungreased cookie sheet.
Bake 9 to 11 minutes or until golden brown around edges. Cool slightly; remove from cookie sheet to wire rack. Place peanut butter cup upside-down on center of each cookie so that bottom of peanut butter cup can be seen. (Do not press cup into cookie; heat from cookie will melt peanut butter cup enough so that it will stick when cool.) Cool completely.
Place sheet of waxed paper under cooling rack. Prepare PEANUT BUTTER GLAZE. One cookie at a time, completely cover top and sides of peanut butter cup with about 1 teaspoon glaze, allowing glaze to run onto brim of cookie hat. Use small knife or spatula to evenly spread glaze on cookie hat brim. (If glaze begins to get too thick to easily use, heat in microwave at MEDIUM several seconds to soften.) Allow glaze to set. Decorate as desired. About 42 cookie hats.
PEANUT BUTTER GLAZE:
Place remaining 1/2 cup peanut butter chips (reserved from cookie) and 1/4 cup milk in medium microwave-safe bowl. Microwave at MEDIUM 1 minute; stir until smooth. Stir in 1/2 teaspoon vanilla extract. Gradually add 1-1/2 cups powdered sugar, beating with whisk until smooth. Add additional milk, 1/2 teaspoon at a time, for desired consistency. 1 cup glaze.