01 -
Preheat oven to 425°F (220°C). Line a 12-cup muffin tin with paper liners or grease with cooking spray.
02 -
In a small bowl, combine melted butter, flour, granulated sugar, brown sugar, and cinnamon. Mix with a fork until crumbly texture forms. Set aside.
03 -
In a large bowl, whisk together flour, pumpkin pie spice, cinnamon, baking powder, baking soda, and salt until well combined.
04 -
In a separate bowl, whisk together pumpkin puree, vegetable oil, sour cream, eggs, vanilla extract, brown sugar, and granulated sugar until smooth and well blended.
05 -
Pour wet ingredients into dry ingredients and gently fold together with a large spoon until just combined. Do not overmix to ensure tender muffins.
06 -
Using an ice cream scoop or large spoon, divide batter evenly among muffin cups, filling each about 2/3 full. Sprinkle streusel topping generously over each muffin.
07 -
Bake for 5 minutes at 425°F, then reduce temperature to 375°F (190°C) and continue baking for 15-18 minutes until a toothpick inserted in center comes out clean or with just a few moist crumbs.
08 -
Cool muffins in pan for 5 minutes, then transfer to a wire rack to cool completely. Serve warm or at room temperature.