5 oz. pumpkin purée (use canned or fresh, but make sure it is pure pumpkin - this is 1/3 of a 15 oz. can or a bit more than 1/2 cup)
1/2 stick unsalted butter
3 oz. (a bit less than 1/2 cup) pumpkin purée
1/2 teaspoon vanilla
1/2 teaspoon cinnamon
1/4 teaspoon nutmeg
1 pound powdered sugar
Preheat the oven to 350° F, and line your tins with 9 liners.
Beat the butter and two sugars on medium until creamed. Add the egg.
In a separate bowl, sift together the flour with the baking powder, baking soda, and spices.
Add the vanilla extract to the buttermilk.
Alternate adding the wet and dry ingredients until just combined, then mix in the pumpkin purée.
Scoop into tins with a ice cream scoop or your preferred method, filling about 3/4. Bake for about 22 minutes, turning halfway through. Cool for 5 minutes in pans, then cool completely on a rack before icing.
For frosting: Beat together the room temperature butter and pumpkin purée until as smooth as possible. Add the vanilla and spices. Slowly add the powdered sugar, mixing well.