Preheat your waffle iron according to appliance instructions (I have a simple Cuisinart iron and heat it on setting #4).
Whisk together the flour, baking powder, and salt in a large mixing bowl.
Add the peanut butter, flax, maple syrup, plant milk, and vinegar to a blender. Blend till smooth. Add the wet ingredients to dry and whisk till smooth (a few clumps is fine).
Spray the waffle iron well. Add the batter in 1/2 cup scoops and cook according to appliance instructions till each waffle is done. Store the waffles in the oven on a low setting, or enjoy right away, with toppings of choice.