Preheat your oven to 350°F. Line a muffin tin with 12 paper liners.

Prepare the streusel. In a small bowl, combine flour, brown sugar, cinnamon and salt. Add the cold butter cubes and use a fork or your fingers to mix until the mixture resembles coarse crumbs. Set aside.

In a large bowl, whisk together the vegetable oil, granulated sugar and brown sugar until smooth. Add the eggs one at a time, beating well after each addition. Stir in the pumpkin puree, buttermilk and vanilla extract until well combined.

In a separate bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, cloves and kosher salt.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix the batter.

Divide the batter evenly among the muffin liners, filling each almost completely full. Sprinkle the prepared streusel generously over the top of each muffin.

Bake for 20–25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

Let the muffins cool in the tin for 10 minutes, then transfer to a wire rack to cool completely.