Preheat the oven to 350°F. Line a muffin tray with cupcake liners (or coat with non-stick spray) and set aside.
Add the flour, baking powder, salt, and lemon zest to a large bowl and whisk to combine.
Pour the almond milk, oil, apple cider vinegar, and vanilla into the dry ingredients and stir until just combined. Do not overmix or the muffins will become tough.
Add the blueberries and gently fold into the batter (reserve about ¼ cup for topping the muffins, if desired).
Fill the muffin cups with the batter, dividing it as evenly as possible. You will get 12-18 muffins, depending on how big you want them.
Top the batter-filled muffin cups with additional fresh blueberries, and sprinkle with sugar, if desired.
Bake the muffins for about 25 minutes (30 minutes if using frozen blueberries) or till a toothpick inserted in the center comes out clean.
Remove from the oven and allow muffins to cool in the tray for about 10 minutes. Then remove them from the tray and place them on a wire rack to prevent the bottoms from becoming soggy.
Enjoy while warm, or allow to cool completely before storing. Store muffins in an airtight container for 2-3 days, or in the refrigerator for 3-4 days.