1. Set oven to 350 degrees.
2. In a bowl, mix together the pumpkin puree and sugar.
3. Stir in oil and buttermilk.
4. Beat the eggs lightly; add to the mixture.
5. In another bowl, mix together flour, baking powder, baking soda, spices and salt Add to the pumpkin mixture; stir JUST until moistened (lumps in the batter is okay).
6. Stir in nuts (if using), and cranberries.
7. Scoop into regular size, or mini size muffin tins which have been sprayed with oil, or generously buttered, or lined with paper liners.
8. Bake for about 30-35 minutes (less time for mini muffins, about 20 minutes), or until the muffins test done.
9. Note: the cranberries can be replaced with mini chocolate chips if desired.