Grease eighteen 2-1/2-inch muffin cups or line with paper bake cups; set aside. In a medium bowl, stir together flour, baking soda, cinnamon, salt, and cloves; set aside.
In a large bowl, beat sugar and shortening with an electric mixer on medium to high speed until well mixed. Add molasses and egg; beat well. Add flour mixture and pumpkin alternately to molasses mixture, beating on low speed after each addition just until combined.
Spoon batter into prepared muffin cups, filling each about two-thirds full. Bake in a 400 degree F oven about 20 minutes or until a toothpick inserted near centers comes out clean. Cool in muffin cups on wire rack for 5 minutes. Remove from muffin cups. Cool completely. Frost, if desired. Makes 18 cupcakes.