Preheat oven to 350 and spray a 12 cup muffin cup tray with cooking spray.
Sift together the flour, sugars, baking soda, salt and spice mix in a large bowl.
In a separate bowl use a spatula to mix the eggs, oil, pumpkin and vanilla extract. Mix well.
Pour wet ingredients into dry ingredients and mix lightly with spatula until just combined. If using chocolate chips or nuts, add them now. Scoop muffin mix into the tray and place in the oven for 20 minutes.