COMBINE flour, cocoa, baking powder and salt in small bowl. Melt morsels in small, heavy-duty saucepan over lowest possible heat; stir until smooth. Beat sugar, 1/3 cup peanut butter, butter and vanilla extract in large mixer bowl until creamy. Beat in melted chocolate. Add eggs one at a time, beating well after each addition. Gradually stir in flour mixture. Cover; refrigerate just until firm.
PREHEAT oven to 350° F.
SHAPE into 1-inch balls; press thumb into tops to make about 1/2-inch depressions. Place on ungreased baking sheets. Fill each depression with about 1/2 teaspoon peanut butter; press 3 Goobers into peanut butter.
BAKE for 10 to 15 minutes or until sides are set. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.