Add your egg whites to a shallow bowl with the milk, vanilla extract, brown sugar, and cinnamon. Whisk until combined to form your egg wash.
4 large egg whites, ¼ cup milk, half and half, or heavy cream, 1 teaspoon vanilla extract, 1 teaspoon brown sugar, ½ teaspoon cinnamon
Add about 2 tablespoons of butter to a large nonstick frying pan over medium heat and allow butter to melt, tilting the pan to coat the entire bottom with butter.
4 tablespoons unsalted butter, for frying
Once your pan is hot, dip the bread into the flavored egg white wash, one slice at a time, coating both sides and transferring immediately to the hot pan.
4 slices day-old bread
Allow your French Toast to fry for 2-5 minutes before flipping and cooking on the other side. Both sides should be golden brown before removing from the pan.
Repeat for all 4 slices of bread, adding more butter to the pan as needed. Serve with syrup of choice (optional).
¼ cup maple syrup, for serving