Preheat the oven to 400ºF or 200ºC and line a standard muffin tin with 12 paper liners.
Mix ½ cup (120 milliliters) of the non-dairy milk and the vinegar in a small bowl until well combined. Let rest for at least 5 mins at room temperature to thicken and curdle.
In a small bowl, toss together the blueberries with 1 tablespoon of the flour to prevent them from sinking to the bottom of the muffins. Set aside.
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
Add the milk and vinegar mixture, remaining milk, oil, and vanilla extract to the dry ingredients, and stir until JUST combined. Don't over-mix. Then add the blueberries and stir again.
Divide batter into muffin tin filling liners to the top or until all of the batter is used up. Top with a few extra blueberries, if desired.
Bake for 20 to 30 minutes or until a toothpick comes out clean. The muffins will only have a very slightly golden brown color.
Remove from the oven and allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.