Preheat oven to 350F. Line a 12-cup muffin tin with paper liners.
In a medium bowl, combine flour, baking powder, baking soda, pumpkin pie spice and salt. Stir with a whisk to combine.
In another bowl, beat the butter and white sugar until it is light and fluffy. Then add vanilla and eggs, one at a time, beating well after each addition. Add flour and buttermilk alternately, beginning and ending with flour, beating just until combined.
Divide batter evenly between muffin cups. Sprinkle the tops of the muffins with the streusel topping. Bake at 350F for 18-20 minutes, until golden. Let stand 5 minutes before transferring to cooling rack.
To Make the Topping:
In one bowl, melt the butter. In another bowl, mix together the brown sugar, white sugar and pumpkin pie spice.
Dip the tops of the muffins in the butter and then dip into the sugar spice mixture. Twist the top around to really get it coated. We double dipped most of them. Butter, sugar-spice, butter, sugar spice.
Eat for breakfast or after school, to get ready for Fall! YUM!