1. Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius). Line a muffin tin with paper holders.
2. In a bowl, combine flour, baking powder, baking soda, salt, brown sugar, cinnamon, nutmeg, ginger, and allspice. Mix well.
3. Make a well in the center. Add egg, oil, soy milk, zest, juice, pumpkin, and apple. Stir just until blended. (Overmixing muffins can cause them to be flat and rubbery.)
4. Spoon batter into prepared muffin tin. I use a full 1/3 measuring cup to do this, so all the muffins are even.
5. Place streusel ingredients in a small bowl and mix together with a fork. Sprinkle over the tops of the muffins.
6. Bake for 22 minutes. Carefully remove from the pan and cool on wire rack.
You can put part of the crumbs on the bottom of the muffin, pressing down to form a crust. If the streusel looks like it’s getting too dark while baking, cover loosely with parchment paper until finished baking. The muffin itself needs the full baking time.
You can use any other orange fall vegetable in place of the pumpkin — pureed butternut squash, sweet potato, or a combo of a few. I used pumpkin for convenience.