• Preheat the oven to 350 degrees.
• Line 18 muffins cups with paper liners or spray with non stick cooking spray.
  
• In a large mixing bowl, whisk together the flour, baking soda, baking powder, corn starch, cinnamon, ginger, nutmeg, cloves, allspice, and cardamom.
  
• In the bowl of a mixer, add the butter and sugars, creaming until fluffy. That takes 2-3 minutes.
  
• Add the egg and the vanilla and mix to combine.
  
• Add the pumpkin and mix to combine. It may look a bit curdled, but it all comes together with the dry ingredients.
  
• Scrape the side and bottom of your mixing bowl to make sure everything is incorporated. You may need to mix again, very briefly.
• Add the dry ingredients, one half at a time, mixing each time.
• Mix until combined, again, making sure everything on the sides and bottom gets incorporated.
• Fill each muffin cup about 2/3 full.

Streusel Topping

• Melt 5 tbsp of butter.
• Put the flour, brown sugar, and cinnamon in a mixing bowl and whisk together.
  
• Add the melted butter to the dry ingredients. Toss the mixture lightly with a fork. You are trying to make crumbs, not a paste, so you don't want to stir. I usually start off with the fork and then use my fingers. If the mixture is too dry, you can add one more tablespoon of melted butter.
• Sprinkle the topping over the muffins, pressing down lightly.
  
• Bake until a toothpick inserted into the center comes out clean, 20-25 minutes.