In a bowl, mix together the buttermilk, pumpkin, egg, and oil.
If you don't have buttermilk, combine 1 and 1/2 cups 2% or whole milk with 2 tablespoons vinegar and allow to stand for about 5 minutes before using it.
Combine the flour, brown sugar, baking powder, baking soda, allspice, cinnamon, ginger and salt in a separate bowl. Stir into the pumpkin mixture just enough to combine. Don't overstir or your pancakes will be dense.
Heat a lightly oiled griddle or frying pan over medium high heat. Pour or scoop the batter onto the griddle, using approximately 1/4 cup for each pancake. Brown on both sides and then remove onto a plate.
Combine the white sugar and cinnamon in a small bowl.
Place the butter in another small bowl.
Dip one side of each pancake into the butter and shake off the excess before transferring it to be coated in the cinnamon-sugar mixture. Dip in that and shake off any excess.