Preheat the oven to 375 degrees.

Combine the soy milk and apple cider vinegar and set aside.

Whisk the flour, baking powder, baking soda, and salt together in a large mixing bowl. In a separate bowl, combine the mashed bananas, sugar, oil, vanilla extract, and curdled soy milk. Mix the dry ingredients with the wet ingredients, then add the blueberries and pecans.

In a separate bowl, mix the rolled oats, margarine, and brown sugar with your fingertips to form course crumbs for the topping.

Scoop the batter into a lightly greased muffin pan. Sprinkle the topping onto the muffins, and bake for about 30 minutes, or until the tops are crispy and golden brown.