Mix together crumble topping ingredients. Set aside.
Mix dry ingredients (flour, baking powder, baking soda, and salt) in a large bowl.
In a separate bowl, mix applesauce, soy milk, vinegar, sugar, melted butter, and vanilla.
Place elderberries in a small bowl and add 1 to 2 tablespoons of the flour mixture. Gently stir the elderberries to coat them with the flour mixture.
Add the wet mixture to the dry mixture and stir until the dry ingredients are just moistened. Add the berries. It’s ok for the batter to be lumpy because you don’t want to over mix so the muffins will be fluffy.
Pour the batter into muffin cups, sprinkle with the crumble topping (optional, but highly recommended), and bake for about 17 to 20 minutes. Let cool for several minutes before serving.
Be careful when stirring after berries are added. Stir very gently so as not to make the berries break apart. If the berries are very ripe, they will be more tender.