For the muffins:

1. Melt the 3/4 cup butter and let cool.
2. Prepare a 12-count muffin tin with paper cups or by greasing it.
3. Preheat the oven to 375°.
4. While the butter is cooling, combine all of the following dry ingredients (1 1/4 cup flour, 3/4 tsp baking soda, 3/4 tsp baking powder, 1/4 tsp salt, 3/4 tsp ground ginger, 3/4 tsp allspice, 3/4 tsp nutmeg,  and 1 tsp cinnamon) in a medium-sized mixing bowl, using a wire whisk.
5. Next, in a separate bowl, combine the cooled melted butter with the 1/2 cup white sugar and 1/2 cup light brown sugar, making sure to break up chunks of brown sugar.
6. Add the two eggs, 1 cup pumpkin pureé, 2 tablespoons milk, and 1 1/2 tsp vanilla to the butter and sugar mixture. Stir well.
7. Add the dry ingredient mixture gradually to the wet mixture, stirring to combine as you add a bit at a time.
8. Spoon the muffin batter evenly into each muffin cup.  They will be about 3/4 of the way full.

For the crumble topping:

1. Melt 4 tablespoons of butter and allow this to cool.
2. While the butter is cooling, use a wire whisk to combine 1/2 cup flour, 1/4 cup white sugar, 1/4 cup light brown sugar, and 1 teaspoon cinnamon.
3. Add the butter and use a fork to mix, creating a crumble texture.
4. Spoon the topping onto the muffin batter, pressing it lightly on top.  Divide the topping evenly and know that this part will be messy!  Add as much topping as the muffins can hold or as much as you desire. I often have a bit of topping left over.
5. Bake at 375° for 18-20 minutes.  A toothpick should come out clean when they are fully cooked.  Allow the muffins to rest on a wire rack, in the muffin pan for 5 minutes before removing them to cool.