Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a large bowl, mix together the pumpkin puree, vegetable oil, sugar, and brown sugar until smooth.
Add the eggs one at a time, mixing well after each addition.
In a separate bowl, combine the flour, baking soda, baking powder, spices, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the chopped nuts gently, if using.
Divide the batter evenly among the muffin cups, filling each about 2/3 full.
Bake for 20-25 minutes or until a toothpick inserted in the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes, then transfer to a wire rack.
Top with cream cheese frosting or enjoy plain.