Sourdough Pumpkin Muffins with Crumble Topping

Melt the butter in a saucepan over medium-low heat.
In a medium bowl, combine the flour, sugars, and cinnamon. Pour the melted butter over top and mix with a fork until no dry bits remain. Set aside to cool while you make the muffin batter.

Preheat oven to 375 degrees. Line a muffin tin. This recipe makes 24 muffins, so if you have 2 muffin tins, line them both. Otherwise, you can make these in batches.
In a large bowl, whisk together the pumpkin puree, eggs, sugar, oil, and discard until smooth. Add in the baking powder, soda, salt, cinnamon, nutmeg, ginger, and cloves and mix to combine. Stir in the flour until just combined. Divide between the prepared muffin cups. Sprinkle a generous amount of the crumble topping over each muffin, breaking the crumbles up with your fingers if they're too big.
Bake 18-20 minutes, until a toothpick inserted into the middle of a muffin comes out clean, or with just a few moist crumbs. Cool for a couple of minutes in the muffin tin until cool enough to handle, then remove to a wire rack to cool completely. Repeat with the remaining batter and crumble topping if making in batches.
Muffins can be kept uncovered for up to a day. After that, store them in a container or a plastic bag, but keep it open slightly. If the topping gets moist, it will soften. Muffins will keep for up to 4 days.