Mix the flours, oats, cardamom and baking powder together.
Mash the bananas in a large mixing bowl. Add the egg and stir until combined. Add the oil and whisk again. Add the milk and vanilla and stir until mixed well.
Add the dry ingredients to the wet ingredients and gently stir until just combined. The batter should be cake-like in texture. It will be thick, not runny, but pourable.
Add the blueberries and stir once more.
Preheat waffle iron. Once iron is ready, spray with cooking spray (not all waffle machines require this)
Add approx 1 cup of batter to the waffle iron (adjust based on size of waffle iron) and cook according to manufacturer instructions. (Mine took 4-5 mins)
Remove and place on a cooling rack. Repeat until batter has finished.
These waffles are not as sweet as regular waffles as they were developed for babies/toddlers. If you are looking to make them sweeter then you can add some maple syrup to the batter or replace the blueberries with chocolate chips! Alternatively, you can serve with a sweet topping. Nutritional information is a ROUGH guide only, calculated using an online nutrition calculator. Does not include any toppings.