Preheat oven to 350 degrees. In a large bowl, beat sugar, oil, pumpkin and eggs until well blended. Combine flour, baking soda, salt, baking powder and cinnamon in a small bowl. Gradually beat into pumpkin mixture until well blended.
Line cupcake pan with paper liners. Fill each line three quarters full. Bake 18-22 minutes or until a toothpick inserted in center comes out clean. Cool 10 minutes before removing to wire racks.
Beat cream cheese and butter together for several minutes. Mix in confectioner's sugar and vanilla. Beat until smooth and creamy.
Using an apple corer poke a hole in the center of each cupcake. If you don't have an apple corer you can also cut a 1 inch by 1 inch circle in the center using a sharp knife. Set aside cake pieces.
Fill hole with frosting and add a little frosting on the top. Place reserved cake pieces on top and garnish with one clove.