Combine the sugar, oil, pumpkin and eggs in a large mixing bowl. In a separate bowl, whisk together flour, baking powder, baking soda, cinnamon.
Add flour mixture to the wet mixture and mix on high speed for about 5 minutes until batter is smooth and no clumps of flour remain.
Grease cupcake pumpkin molds. Spoon batter into each mold until about 1/2 full.
Add one heaping teaspoon of Nutella into the middle of each mold. Spoon more batter into each cupcake liner so that the Nutella is covered and cupcake molds are about 2/3 full.
Bake in preheated oven for approximately 15-20 minutes or until tops are firm and a toothpick inserted on the side comes out clean. If you insert it where the Nutella is, only melted Nutella should cling to the toothpick and not uncooked batter crumbs.
After cakes have cooled, use ready made green icing to pipe leaves on top. Decorate jack-o-lantern faces with edible black pen.
