Preheat oven to 375F (190C) and line a 12-count muffin tin with paper liners (or lightly grease and flour). Set aside.

Combine melted, cooled butter, granulated sugar and brown sugar in a large bowl and stir well.

Stir in eggs. Add pumpkin puree, milk, and vanilla extract and stir well.

In a separate bowl, whisk together flour, baking powder, baking soda, salt, pumpkin spice, and cinnamon until well-combined.

Add your dry ingredients into your wet and gently stir until just combined, taking care to not overmix the batter.

Evenly divide muffin batter into prepared muffin tins (filling each ¾ full). Set aside while you prepare your streusel.

Prepare your streusel by whisking together flour, sugars and cinnamon.

Pour the melted butter into the mixture and, using a fork, stir until crumbles form. Don't overwork the streusel or you'll end up with a paste, you want it to be nice and clumpy!

Using your hands, evenly divide streusel over muffin batter, piling the streusel over the batter and gently pressing the topping into the batter.

Bake on 375F (190C) for 17-19 minutes or until a toothpick inserted in the center comes out clean or with a few moist crumbs. Allow muffins to cool in muffin pan for 5 minutes before carefully removing to a cooling rack to cool completely.

If desired, make glaze by whisking together powdered sugar and milk. Drizzle over cooled pumpkin muffins