Heat oven to 350°F.
Prepare cake mix according to package directions with the eggs and oil, but using buttermilk in place of water.
Spoon batter into cake pan, filling halfway full.
Bake for 15-20 minutes.
Remove cupcakes from the pan and place on a cooling rack. Once cupcakes are completely cooled off, use a serrated knife and trim the bottoms of each cake to remove any doming that may have occurred during baking, thus creating a flat surface.
Next, place a small dollop of icing onto the cut side of the cake, and then sandwich a second cake on top, lining up the pumpkin patterns so the top and bottom pieces match. Cut the vanilla wafer cookies into ½ inch pieces to create the “stem.” You can also use pretzels as the "stem."
Decorate pumpkins as desired. Allow icing to set, then transfer finished mini pumpkins to a platter for serving.
Get creative and add whatever toppings, colors, and decorations you want.