Preheat a waffle iron according to the manufacturer’s instructions; spray the inside with cooking spray.

Whisk almond milk, applesauce, egg, chia seeds, and vanilla extract together in a bowl; let sit until chia seeds start to thicken mixture, about 2 minutes.

Whisk flour, oats, flax seed meal, baking powder, sugar, and salt into almond milk mixture until batter is smooth.

Scoop 1/2 cup batter into the preheated waffle iron and cook until crisp and golden, about 5 minutes per waffle. Repeat with remaining batter.