Preheat the oven to 350 degrees F (175 degrees C). Line 12 cups of a mini muffin tin with paper liners or spray with cooking spray.
Mix blueberries, flour, sugar, applesauce, soy milk, soy margarine, baking powder, vanilla extract, and salt together in a bowl. Spoon batter into muffin cups, filling them 3/4-full.
Bake in the preheated oven until tops are firm, about 35 minutes. Cool slightly on a rack.