1. Remove wrappers from peanut butter cups. Line 24 small muffin cups (1-3/4 inches in diameter) with paper or foil bake cups.
2. Beat butter, sucralose, granulated sugar, egg and vanilla in large bowl until well blended. Stir together flour, cocoa, baking soda and salt; gradually add to butter mixture, beating until well blended. Refrigerate dough 30 minutes or until firm enough to handle.
3. Heat oven to 350 F. Shape dough into 24 equal balls; place one in each prepared muffin cup. Do not flatten.
4. Bake 8 to 10 minutes or until puffed and toothpick inserted into center comes out clean. Remove from oven. Immediately press one peanut butter cup into each cookie. Cool completlely. 2 dozen cookies.
**Light margarine may be substituted. Do not refrigerate batter; divide evenly into prepared muffin cups. Bake as above. Brownie cups will be more cake-like.