Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or grease with non-stick spray.

In a large mixing bowl, whisk together the canned pumpkin puree, granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract until well combined. This mixture will create a moist base for the muffins.

In another bowl, sift together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt. Sifting helps to aerate the flour and remove any lumps.

Gradually add the dry ingredients to the wet ingredients, stirring gently with a spatula until just combined. Be careful not to overmix, as this can lead to dense muffins.

In a small bowl, combine the flour, granulated sugar, brown sugar, melted butter, and cinnamon. Mix with a fork until crumbly. This will create a crunchy topping for the muffins.

Spoon the muffin batter into the prepared muffin tin, filling each cup about ⅔ full.

Sprinkle the streusel topping generously over each muffin.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean. This ensures that the muffins are fully cooked inside.

Allow the muffins to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely.