Preheat your oven to 400 degrees Fahrenheit and place liners in your muffin tin and spray them lightly with oil.
Next, combine your almond milk and apple cider vinegar in a large measuring cup or small bowl and set aside to curdle, this will become your “buttermilk”.
In a large bowl whisk together the flour, sugar, baking powder, salt, and cornstarch.
Then add in the oil, vanilla, and milk/vinegar mixture into the dry ingredients and combine everything together. It’s okay if there are small lumps in the batter.
Next, in a small bowl add the blueberries and 1 teaspoon of flour and coat the blueberries in the flour. Be sure to save a few blueberries on the side for topping the batter before baking.
After the blueberries have been coated in a light layer of flour, add them into the muffin batter and gently fold in.
Next fill your prepared muffin liners ¾ the way full with the batter and then top the batter with a couple of small blueberries and a generous sprinkle of granulated sugar over the tops.
Bake in your oven for 20-25 minutes until they are ever so slightly golden and a toothpick comes out clean.