Lightly grease twelve 2-1/2-inch muffin cups; set aside. In a medium bowl, combine the flour, oats, baking powder, baking soda, pumpkin pie spice and salt. Make a well in the center of the flour mixture.
In another medium bowl, combine egg, milk, pumpkin, brown sugar and oil. Add all at once to flour mixture. Stir just until moistened (batter should be lumpy). Fold in sunflower seeds.
Spoon batter into prepared muffin cups, filling each three-fourths full. Sprinkle batter with Streusel Topping. Bake in a 400 degree F oven for 20 to 25 minutes or until a wooden toothpick inserted in the center comes out clean. Cool in muffin cups on a wire rack for 5 minutes. Remove from muffin cups; serve warm. Makes 12 servings.
In a small bowl, stir together brown sugar, flour and pumpkin pie spice. Cut in butter until the mixture resembles coarse crumbs. Stir in sunflower seeds.