Preheat oven to 350°F. Line muffin pan with liners. Set aside.
In a small bowl, whisk together pumpkin purée, vegetable oil, prepared egg replacer, vanilla extract, and sugar. Set aside.
In a medium sized bowl, whisk together all your dry ingredients. Add dry ingredients to your bowl of wet ingredients. Combine well with a spoon or a spatula.
Fill your muffin pan cups with batter. Sprinkle streusel topping over each muffin and bake for 50-55 minutes. Once muffins are cool enough to remove from the pan, place them on a cooling rack so that the moisture can evaporate from the bottoms.
Streusel topping
In a small bowl, combine all your streusel ingredients. You can use your hands or pastry blender to do this. Pour over the tops of your muffins before baking.