Mix baking soda,flax seeds & flour,add powdered sugar in a bowl.
Mix vinegar with milk (very lightly warm),so that it curdles a bit.
Add milk and vinegar mix to bowl,slowly start mixing all ingredients.
Add Oil to the mix and keep on mixing.
Add blueberries to the cake mix,transfer the contents to a baking tin.
Garnish with few berries,bake for at least 35-40 minutes at 160C(fan forced) or until the toothpick comes out clean from the center of the cake.
Let it cool on a wire rack,cut into slices.