Heat griddle to 350° or you can cook the French toast in a skillet pan over medium-high heat. Spray the griddle or skillet pan with non-stick cooking spray.
In a mixing bowl add the milk and flour. Stir with a whisk until combined well.
Add in the eggs, sugar, vanilla extract, and ground cinnamon. Stir well with a whisk until combined. Pour into a shallow dish like a pie plate or something similar. * The ground cinnamon tends to chunk up in the wet batter, that's fine, just mix it as well as you can. The cinnamon might not be fully incorporated and smooth in the mixture but that's ok.
Working one piece of bread a time, fully submerge the bread in the wet batter, making sure that all the bread is covered in the batter.
Place on the hot griddle or skillet pan and cook one each side for about 3-4 minutes, or until lightly browned.* If wanted, spread one side with butter after you flip it.
Serve with maple syrup and a dusting of powdered sugar.
