Make the flax egg: In a small bowl, combine ground flax seeds and water. Set aside for 5 minutes.
Make the vegan buttermilk: add 1 tbsp lemon juice or vinegar to a measuring jug. Add soy milk or almond milk up to the 1 cup line. Allow to sit for a minute. It will thicken and curdle
In a large bowl, sift together flour, sugar, salt, baking powder and baking soda and whisk to combine.In a separate bowl add buttermilk, vanilla and melted butter.
Add the flax egg to the buttermilk and whisk to combine.
Pour the wet ingredient mixture into the dry ingredients and stir till mostly incorporated. The batter should be thick and a little lumpy, but without any visible streaks of flour.
Gently fold in the blueberries. Set the batter aside for 10-15 minutes.
Heat a heavy-bottomed, non-stick pan over a medium heat and lightly grease it with oil.