1. Trim short ends of pound cake; discard. Cut cake crosswise into eight 1" slices. Use a 2 1/8" and a 1 1/8" round cutter to cut circles from each slice.
2. Arrange cake circles on a wire rack placed on top of a baking sheet. Attach smaller circles to larger circles with a dot of vanilla frosting.
3. Heat remaining vanilla frosting in microwave, stirring every 5 seconds, until slightly loosened. Pour frosting over each cake to cover completely.
4. To add chocolate topping, refrigerate iced cakes to set, about 15 minutes. Then spoon chocolate frosting into a resealable bag; press out excess air. Heat in microwave, about 5 seconds total, until slightly melted; message bag to even out texture. Snip a small corner from bag and pipe on top of cakes, allowing frosting to drip down over edges.
5. While frosting is still wet, decorate with sprinkles and candy decors.