In a large bowl, whisk together the flour, baking soda, spices and salt. Set aside.
2 Cups Flour, 1 teaspoon Baking Soda, 2 teaspoons Cinnamon, 1 1/2 teaspoons Pumpkin Pie Spice, 1/2 teaspoon Salt
In another bowl, whisk together the oil, sour cream, buttermilk and sugars. Add in the eggs and whisk again, but be sure to not over mix.
1/3 Cup Canola Oil, 1/4 Cup Sour Cream, 1/4 Cup Buttermilk, 1/4 Cup Brown Sugar, 3/4 Cup Sugar, 2 Eggs
Dump the dry ingredients, and pumpkin on the wet ingredients and switching to a rubber spatula or wooden spoon, gently fold the ingredients together just until a few streaks of flour remain.
1 1/3 Cups Pumpkin
Fill jumbo cupcake liners in a jumbo pan 2/3 full of batter. Or use a regular muffin tin.
Add a dollop of Nutella on the top of each muffin.
2/3 Cup Nutella
Using a toothpick, gently swirl the Nutella into the muffin batter.
Bake for 23-28 minutes and then remove from the oven to cool completely.
Sprinkle the tops with powdered sugar and serve.
Notes
Muffins will keep for 2 days at room temperature, or store in the refrigerator for up to 1 week.