"I have made these for kids and adults alike and they all love them. Chocolaty but not too sweet, these whole-grain waffles are sure to please any age and make you feel good about what your kids and/or guests are eating. Letting the batter sit overnight allows the chia seeds and oats to soften, so the batter is smooth and waffles fluffy. You will not even know they are vegan, only delicious."
Mix flour, oats, sugar, cocoa powder, chia seeds, baking powder, and salt together in a large bowl. Add 3 cups almond milk and coconut oil; stir with a wooden spoon until batter is just combined. Cover and refrigerate, 8 hours to overnight.
Preheat a Belgian waffle iron according to manufacturer's instructions.
Stir 1 1/2 to 2 cups almond milk into the batter to thin it to the consistency of cake batter.
Scoop 1/2 cup batter onto the preheated iron and spread to the edges. Close iron and cook until iron stops steaming, about 5 minutes. Repeat with remaining batter.