In a small bowl, whisk together the flour, baking powder, salt, sugar, and cinnamon until blended. In a medium bowl, whisk together the milk, oil, vanilla, and eggs.
Add the wet ingredients to the dry ingredients, and mix until just combined (a few small lumps are okay). Let rest five minutes.
While the batter is resting, preheat your waffle iron. Add the batter and cook according to your waffle maker's directions. (For my belgian waffle maker, 1 cup of batter cooked for 4 minutes was perfect.)
Serve warm, and top with syrup, whipped cream, and cinnamon, if desired.