For the Cupcakes: Preheat the oven to 350°F/177°C, and line 18 muffin cups with paper liners. Set aside.
In a medium bowl, sift together the flour, cinnamon, nutmeg, cloves, baking powder, baking soda, and salt, and whisk to combine.
In a large mixing bowl fitted with the paddle attachment, beat the butter, brown sugar, and white sugar on medium until fluffy and creamy. With the machine running, add the oil in a slow stream. Once blended, add the eggs one at a time, mixing after each addition, then the pumpkin purée, and continue beating until smooth. Add half the flour mixture, beat on low to combine, then add the milk and beat again. Add the remaining flour mixture and beat until just combined. Divide the batter among the prepared muffin cups, filling each one about 3⁄4 full.Bake until a toothpick inserted in the center of a cupcake comes out clean, 15 to 25 minutes (it took my oven 20 minutes). Let cool in the pans for 5 minutes, then remove the cupcakes and transfer to a wire rack to cool completely.
For the Frosting: In a large mixing bowl fitted with the paddle attachment, beat the butter until light and fluffy. Sift the powdered sugar directly into the bowl, then add all the spices and the vanilla, and beat until smooth and creamy. *I added 1 tablespoon of milk to thin it a wee bit. You decided. :)
Once the cupcakes are completely cool, pipe or spread a generous layer of frosting on top of each one and sprinkle with a pinch of cinnamon. Serve and enjoy!