Step 1

Preheat your oven to 350°.

Step 2

Line a 6-count jumbo muffin tin with jumbo muffin liners. (You can make these using a 12-count regular muffin tray, but the muffins will only bake for about 15-18 minutes.)

Step 3

In a large bowl, whisk together the flour, baking soda, pumpkin spice, and cinnamon until combined.

Step 4

Add the oil, sour cream, brown sugar, granulated sugar, eggs, and pumpkin. Mix just until combined.

Step 5

Divide the batter among the 6 muffin cups.

Step 6

In another bowl using your fingers to combine the ½ cup flour, ¼ cup granulated sugar, 3 tablespoons brown sugar, 1 teaspoon cinnamon, and butter until coarse crumbs form.

Step 7

Sprinkle the crumb topping all over each muffin.

Step 8

Place in the oven and bake for 25-30 minutes when a toothpick inserted in the middle comes out clean.

Step 9

Remove from the oven and cool.

Step 10

Dust the tops with powdered sugar and serve!