- Preheat the oven to 375°F. Line the muffin tin with muffin liners and set aside.  
- In a medium-sized bowl, add in flour, baking soda, baking powder, cinnamon, nutmeg, allspice, cloves, ginger, and salt. Mix together and set aside. - 2 1/3 cups all-purpose flour, 1 tsp baking soda, 1 1/2 tsps baking powder, 2 tsps cinnamon, 1/4 tsp allspice, 1/4 tsp ginger, 1/8 tsp nutmeg, 1/2 tsp salt, 1 tbsp cornstarch 
- In a large bowl, add brown sugar, white sugar, oil, eggs, pumpkin, sour cream, and vanilla. Whisk together until well combined. - 1  cup dark brown sugar, 1 3/4 cups pumpkin puree, 3 large eggs, 2/3 cups oil, 1/3 cup sour cream, 1 tsp vanilla, 1/2 cup white sugar 
- Pour the dry ingredients into the wet and using a spatula, gently fold to create a soft muffin batter. Mix in the chocolate chips. - 1 cup semi-sweet chocolate chips 
- Evenly divide the batter between the liners, they should be almost full. See photos for reference. Using a cookie scooper helps big time to minimize the mess. Sprinkle extra chocolate chips on top. 
- Bake the muffins at 425°F for 5 minutes, then lower the oven to 375℉ and continue baking for 15-20 minutes. The muffins are ready when a toothpick inserted comes out clean.  
- These muffins stay fresh at room temperature for a few days, or in the refrigerator in an airtight container for up to 1 week!