Preheat the oven to 200 degrees Fahrenheit. This will be to keep the sticks warm while you make them in batches.
Toast the bread on a rimmed baking sheet in the oven for 15 minutes, flipping them over in the middle of toasting. Alternatively, you can leave them out overnight.
In a dish, whisk together 1/2 cup sugar and 2 teaspoons cinnamon. Set aside to use in Step 6.
Whisk together 6 eggs, 1 cup half and half, 3 teaspoons vanilla, 1 teaspoon cinnamon, and 1/4 cup sugar. Ensure that the egg whites are fully broken down by dragging a fork through the batter. Nothing should hang onto the fork as it goes through.
Submerge the toast sticks, turning them several times to ensure they soak up a lot of the batter. I like to push them down in the batter once on each side to fully submerge them. The pieces of bread do not need to sit in the batter to soak.
Heat a nonstick skillet over medium heat. Spray lightly with cooking spray. (Alternatively, if using a traditional skillet, melt 2 tablespoons of butter.) Cook the toast in batches for 2 to 3 minutes on each side or until they are golden brown. When you are done, toss them in the cinnamon sugar mixture and transfer them to a covered baking dish in the warm oven.
Serve with powdered sugar, whipped cream, and maple syrup for dunking.