Combine flour, oats, baking powder and soda, cinnamon and salt in a mixing bowl.
In a separate bowl, whisk together the milk, juice, butter, vanilla and sugar.
Add the wet ingredients to the dry and fold until almost combined. Fold in the grated apple and continue mixing until just combined. Don't overwork the batter you you'll end up with rubbery waffles.
Allow the batter to sit for 5 minutes.
Turn the oven on to a low heat.
Spoon the batter in to the waffle iron in batches and cook for approximately 5 - 7 minutes or until the waffles are slightly crispy. Once most steam has dissipated, the waffle should be ready.
Keep the waffles warm in the oven while you finish cooking all the batter.
Serve with the apple topping and chopped pecans (optional)