Preheat oven to 400°F. Lightly grease a muffin tin or line tin with paper cups.
Stir together flour, sugar, baking powder, and salt in a medium bowl. Toss in blueberries and lemon zest, if using.
Separately, whisk together dairy-free milk, vegetable oil, lemon juice, and vanilla extract.
Gently mix the wet and dry ingredients together. Spoon mixture evenly into prepared muffin tin, filling each tin about two-thirds of the way.
Bake for 20-25 minutes or until tops are golden brown. Remove the pan from the oven and let muffins sit 5 minutes before removing from tin.