Plug in your waffle iron so that it can begin to heat up. Preheat oven to 300°F or heat up a toaster oven to keep prepared waffles warm.
In a mixing bowl, combine the flours, sugar, and baking powder. Stir to combine.
In a separate bowl, combine the milk, ground flax, apple cider vinegar, melted butter, and vanilla. Stir to combine.
Pour the milk mixture into the flour mixture and stir until everything is incorporated. Add frozen blueberries and stir gently to incorporate.
Spray your waffle iron with vegetable cooking spray. Use a spoon or 1/2 cup measuring cup to dispense batter into waffle iron. Use the back of the spoon or measuring cup to make sure every section of the waffle iron is filled, spreading the batter to the edges. Close the lid and cook the waffles for 5–7 minutes, until golden and crispy.
Transfer cooked waffles to a pan in the heated oven to stay warm and continue making waffles until the batter is gone.
Serve warm with vegan butter, peanut butter, jam, maple syrup or your favorite toppings.
Notes
Nutritional estimates are for waffles only and does not include toppings.Most waffle irons have an indicator light to show when the waffles are done. However, I like to cook them just a little bit longer, to make sure they get a crispy crust.You don't need to add additional sodium to these vegan waffles because vegan butter is usually salted. If you're using unsalted butter, you can add up to 1/4 teaspoon.