Grease your skillet generously with olive oil and preheat it over medium-low heat on your stove top.
In a medium bowl, combine the water or non-dairy milk, starch, maple syrup, and cinnamon, and stir well to combine. (I think using a whisk helps it combine faster.)
Dip one slice of bread into the mixture, then quickly flip it over and dip the other side in so that the bread is coated. You don't want it to stay in there too long or it will get soggy. When you lift the bread out of the bowl, let any excess liquid drip back into the bowl.
Place the coated bread into the preheated skillet. It should start sizzling right away. After a minute, slide a spatula under the bread to make sure it isn't sticking to the skillet. (Don't flip it yet, this is just to ensure the coating doesn't totally stick to the pan.)
Flip the bread after 2 to 3 minutes, and cook the other side. In my experience, the first side usually wants to stick to the pan more than the second side does. Continue flipping the bread every minute or two, until it's nice and golden on both sides. Repeat this process with the remaining bread and "egg" mixture until all of the French Toast is cooked. (Stir the egg mixture each time, as the starch has a tendency to sink to the bottom as it rests.)
I like to keep the cooked French Toast slices in a warm oven (around 200ºF) while I finish cooking the rest of the batch. Serve warm with fruit and maple syrup, as desired.