Preheat the oven to 375°F. Line the muffin liners with liners and set aside. This recipe makes 15 muffins total. If you’re using tulip liners like I did, this recipe will make 8-10 of them total. Melt the butter for the streusel and allow to cool for 10 minutes before beginning (must be lukewarm).
In a medium sized bowl, add flour, brown sugar, white sugar, cinnamon, and melted butter. Using a fork, mix this until small crumbs form. Then sprinkle 1 tbsp of extra flour on top and with your fork, gently mix until all the flour is well incorporated. Repeat 3 times until you no flour streaks remain. See photo for reference. Set aside while you make the muffin batter.
1/4 cup white sugar, 1/4 cup brown sugar, 1/2 tsp cinnamon, 3/4 cups flour + 1 tbsp on the side, 6 tbsp butter
In a medium-sized bowl, add in flour, oats, baking soda, baking powder, cinnamon, nutmeg, allspice, cloves, ginger, and salt. Mix together and set aside.
1 3/4 cups all-purpose flour, 1 cup rolled oats, 1 1/2 tsps cinnamon, 1/4 tsp ginger, 1/8 tsp allspice, 1/2 tsp salt
In a large bowl, add brown sugar, white sugar, oil, eggs, pumpkin, sour cream, and vanilla. Whisk together until well combined.
1 cup pumpkin puree, 1/2 cup white sugar, 1/2 cup sour cream, 1/2 cup oil, 2 large eggs, 1 tbsp vanilla
Pour the dry ingredients into the wet and using a spatula, gently fold to create a soft muffin batter.
Evenly divide the batter between the liners, they should be almost or all the way full. Using a cookie scooper helps big time to minimize the mess. Sprinkle streusel on top.
Bake the muffins at 375°F for 18-20 minutes. If using tulip liners, they will bake from 20-25 minutes. The muffins are ready when a toothpick inserted comes out clean. Every oven differs, so keep an eye out after the 18 minute mark.
These muffins stay fresh covered at room temperature for a few days, or in the refrigerator in an airtight container for up to 1 week!