Preheat the oven to 350 °F (175°C).

Mix together all of the crumble ingredients. Add the flour, rolled oats, sugar, ube powder, and butter to a small mixing bowl. Using your hands, mix all of the ingredients together until they form small crumbles. Set aside.

Whisk the dry ingredients. In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.

Add the wet ingredients. Pour in the plant-based milk, oil, vanilla extract, and apple cider vinegar.

Mix. Using a wooden spoon or spatula, mix the batter until no lumps remain. Do not overmix, though, as this could cause the muffins to be denser.

Incorporate the blueberries. Add the blueberries and stir until they are evenly incorporated. Again, do not stir too much – you don’t want to mash the blueberries.

Prepare your muffin pan. Lightly grease the 6 cavities of a muffin pan with butter. Then, place a muffin paper liner in each cavity.

Fill it. Next, fill each cavity until it reaches about three-quarters full.

Top with the crumble. Sprinkle the purple crumble topping evenly on top of each muffin.

Bake. Transfer the muffin pan to the oven and bake for 20-22 minutes or until the tops are golden brown. Allow the muffins to cool down for about 15 minutes before removing them from the pan and transferring them to a cooling rack.

You can store the muffins in the refrigerator for up to 4 days.