Preheat oven to 350ºF (static) or 325ºF (convection).
Oil or line muffin cups and set aside (makes approximately 16 muffins).
If baking from scratch, cream the butter and sugar until the mixture is light and fluffy.
If using my gfJules™ Muffin Mix and you are adding the optional 1/4 cup sugar, cream that with the butter. If you are not adding more sugar to the muffin mix, instead add 1/4 of the muffin mix to the butter and whip.
Next, add the eggs and beat well. Stir in sour cream and pumpkin purée until well blended.
If baking from scratch, use a separate bowl and whisk together all the dry ingredients (including pumpkin pie spice) then add gradually into the wet mixture until thoroughly mixed.
If using my gfJules™ Muffin Mix, simply add remaining mix to the bowl and beat until integrated with pumpkin mixture.
Lastly, fold in chocolate chips, if using.
Spoon the batter into prepared muffin tins, filling two-thirds full. Bake for 25-30 minutes or until lightly browned.
Cool before removing from tins. Makes 12 – 16 muffins, depending on size.