In a medium bowl, mix together all the topping ingredients with a fork until coarse and crumbly. Set aside in the fridge to cool.
60 g plain white flour, 25 g vegan butter, 25 g granulated sugar
To Make the Muffins
Preheat the oven to 220 °C and line a 12 well muffin tray with muffin cases.
If using frozen blueberries, place them in a strainer and rinse under the tap to remove any juice from their exterior then pat dry with kitchen roll.
In a medium bowl, sieve together the plain white flour, baking powder and corn starch. Set aside.
240 g plain white flour, 1 ½ teaspoon baking powder, 1 tablespoon corn starch
In the cup of a blender, place the vegan yoghurt, granulated sugar, melted vegan butter, water, silken tofu and vanilla extract. Blend until smooth. Alternatively blend in a bowl with an immersion blender.
160 g vegan yoghurt, 180 g granulated sugar, 100 g vegan butter, 50 ml water, 50 g silken tofu, 1 teaspoon vanilla extract
Add the blended wet ingredients to the flour mixture and stir until just combined. Do not over-mix - it's ok if the mixture is still lumpy. Add 120g of the blueberries and stir through the batter.
110 g blueberries
Divide the batter between the muffin cases and use the remaining blueberries to push two or three into the top of each muffin. Sprinkle the top of each muffin with the streusel topping.
Place in the oven and bake for 10 minutes before reducing the temperature to 180c and baking for a further 15 minutes. Remove from the oven and allow to cool in the tin for 3 minutes before carefully removing the muffins and leaving to cool on a wire cooling rack until room temperature.