Preheat the oven to 425° F.
Prepare a 13 x 18 inch baking sheet with parchment paper, set aside.
In a 2 cup measuring cup, mix together the plant based milk with the vinegar to make the vegan buttermilk, and set aside to curdle, about 5 minutes.
To make the egg substitute, add the equivalent of four eggs to a small bowl, blend with water, set aside until thick.
Add the oat flour to a medium sized mixing bowl and pour in the vegan buttermilk, egg substitute, vanilla, and blend until there are no lumps.
Set this aside for about 10 minutes and then stir in the salt and baking powder until well combined.
Pour the batter into the lined baking sheet, spreading the batter evenly.
Evenly place the fruit or spices of choice onto the batter before placing into the oven ( I used blueberries ). Skip if not adding anything.
Bake for 20 to 30 minutes, checking at 20 minutes with a toothpick or touching the top for sponginess.
The pancake is done if the toothpick comes out clean and/or the top is firm to the touch.
Remove from the oven and serve hot with your favorite toppings and syrup.
Left overs? Freeze for later.