PREPARATION:
- Beat butter, shortening and peanut butter in large bowl at medium speed of electric mixer. Gradually add powdered sugar, beating until smooth. Add egg yolk and vanilla; beat well. Add flour; mix well. Stir in 1/3 cup ground peanuts. Cover dough; refrigerate 1 hour. Prepare Peanut Buttery Frosting.
- Preheat oven to 350°F. Grease cookie sheets. Shape dough into 1-inch balls. Place 2 balls, side by side and slightly touching, on prepared cookie sheet. Gently flatten balls with fingertips to form into "peanut" shape. Repeat steps with remaining dough.
- Bake 16 to 18 minutes or until edges are lightly browned. Cool on cookie sheets 5 minutes. Remove cookies to wire racks; cool completely.
- Place remaining 2/3 cup ground peanuts in shallow dish. Spread about 2 teaspoons Peanut Buttery Frosting evenly over top of each cookie. Coat with ground peanuts.
