Preheat your oven to 375°F. Spray a muffin tin with non-stick baking spray, then line the cups with baking liners.
Sift together the all-purpose flour, cinnamon, nutmeg, ginger, cloves, allspice, cardamom, baking powder, baking soda, and salt into a large mixing bowl. Set the dry ingredients aside.
In a separate, larger bowl, use an electric mixer to whip together the brown sugar and eggs until very light brown in color and airy. Add the pumpkin puree, melted butter, and vanilla to the bowl and mix on low speed until well blended, or about 1 minute.
Add half of the dry ingredients to the wet ingredients and blend on low speed just until combined. Add the remaining dry ingredients before blending once again, just until the dry ingredients have been incorporated.
Use a number 12 portion scoop or a measuring cup to fill each muffin tin 2/3rd of the way with the batter.
Top each muffin with 1 tablespoon of streusel topping. Bake the muffins for 18-20 minutes, or until the top springs back when lightly pressed.
Remove the muffins from the oven and allow them to cool in the pan for 5 minutes.After 5 minutes, remove the muffins from the pan to cool further, or enjoy them hot from the oven.
Notes
*To use Pumpkin Pie Spice Blend: omit the cinnamon, nutmeg, ginger, cloves, allspice, and cardamom and replace them with 2 tablespoons (13g) of the Pumpkin Pie Spice.
High Altitude Adjustment (I have not tested these adjustments):
Decrease the baking powder to 1 teaspoon.
Decrease the baking soda to 1/2 teaspoon.
To Store:
Transfer the cooled muffins to a food storage bag or container and keep at room temperature for up to 2 days.
Reheat the muffins in the microwave for a freshly-baked taste.
To Freeze:
Transfer the cooled muffins to a food storage bag or container and freeze until solid. Freeze for 2-3 months.
Thaw muffins on the countertop. Reheat in the microwave for a fresher flavor.