Preheat waffle iron according to manufacturer’s directions and spray generously with nonstick cooking spray.
In a large bowl, whisk together the flour, oats, cinnamon, brown sugar, baking powder, and salt. Add the eggs, milk, oil, and vanilla and mix until combined.
Scoop by 1/3 - 1/2 cupfuls onto hot waffle iron and cook, according to manufacturer's instructions, until waffles are done.
Serve immediately topped with your favorite toppings.
Notes
To keep waffles crispy in between cooking, place on wire baking rack to cool.