In a large bowl whisk together the sugars, pumpkin puree, eggs, vanilla, and vegetable oil until fully combined.
Mix the wet ingredients
Place a sieve on top of the bowl and add all of the dry ingredients and sift into the wet ingredients.
Add dry ingredients
Gently fold the dry into the wet, being careful not to over-mix !
In a medium bowl mix flour, brown sugar, butter, oats, and pumpkin pie spice. Now you'll rub in the butter until you get thick clumps.
Make the Topping
Be careful you don't want to completely rub the butter in so it disintegrates.
Rub the ingredients
Sprinkle the streusel topping heavily over muffin batter and bake muffins
Prepare and Bake
In a small bowl mix together powdered sugar, maple syrup, maple extract, and milk.
Make the Glaze