Prepare the flax egg: In a small bowl, mix 1 tablespoon of ground flaxseed with 3 tablespoons of water. Let it sit for 5 minutes to thicken. Mix dry ingredients: In a large mixing bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon (if using).
Mix wet ingredients: In a separate bowl, combine the plant-based milk, maple syrup, melted dairy-free butter, vanilla extract, and flax egg.
Combine wet and dry ingredients: Pour the wet ingredients into the dry ingredients and stir gently until just combined. Do not overmix.
Heat the waffle iron: Preheat your waffle iron according to the manufacturer’s instructions. Grease it lightly if necessary. Cook the waffles: Pour enough batter into the preheated waffle iron to cover the surface, close the lid, and cook for 3-5 minutes, or until golden and crispy. Repeat with the remaining batter. Serve: Remove the waffles carefully from the iron and serve immediately with your favorite toppings such as fresh fruit, maple syrup, or dairy-free whipped cream.