Preheat the oven to 350°F (175°C) and grease a muffin tin.

In a large bowl, whisk together pumpkin puree, granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract until smooth.

In another bowl, mix together flour, baking soda, baking powder, cinnamon, nutmeg, and salt.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined.

In a small bowl, combine flour, brown sugar, and cinnamon.

Cut in the cold butter until the mixture resembles coarse crumbs.

Scoop the muffin batter into the prepared muffin tin, filling each cup about 2/3 full.

Sprinkle the streusel topping evenly over each muffin.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.