Preheat oven to 350° F.
Insert liners into a cupcake tin.
In a large mixing bowl, mix the butter and sugar with either a handheld or an electric whisk. Add the eggs, pumpkin puree, vanilla, and cinnamon or pumpkin spice, and mix well.
In a medium bowl, combine the rest of the dry ingredients (flour, baking powder, baking soda, salt).
Add the dry ingredients to the wet ingredients, and mix until combined and no lumps remain in the batter.
Add the batter to the cupcake tin until each cup is three-fourths full.
Bake for 20 minutes or until a toothpick inserted comes out clean.
To make the frosting, add Cheryl's buttercream to a bowl and mix in the cinnamon until it is distributed evenly. Add the frosting to a piping bag. Once the cupcakes are cool, pipe the frosting onto each cupcake.
Top with an extra sprinkle of cinnamon, if you wish.
