1. Melt 1/2 cup peanut butter chips; cool.
2. Heat oven to 375°. Beat butter, 1/2 cup granulated sugar, brown sugar, egg and vanilla in large bowl on medium speed of mixer until fluffy. Beat in melted peanut butter chips. Stir together flour, cocoa and baking soda; stir into peanut butter mixture until well blended.
3. Shape dough by level tablespoons into balls; roll in granulated sugar. Place on ungreased cookie sheet; flatten cookies to 1/4-inch thickness with bottom of glass. Press thumb in center or each to make an indentation.
4. Bake 6 to 8 minutes or just until set. Remove from oven. If necessary, using tip of spoon, press indentation in center of each cookie; immediately place 1 teaspoonful peanut butter chips in each indentation. Let stand 1 to 2 minutes or until chips are softened; spread. Garnish each with 3 chocolates, if desired. Remove from cookie sheet. Cool completely. Makes about 30 cookies.