Prepare the custard mixture. In a large mixing bowl, whisk together the eggs, milk, sugar, vanilla, cinnamon, and a pinch of salt until smooth.
Heat the skillet. Place a large nonstick skillet or griddle over medium heat. Add 1 tablespoon of butter and let it melt until it sizzles.
Dip the bread. Take each slice of bread and dip it into the egg mixture, coating both sides evenly. Let the bread soak for 10–15 seconds, but don’t let it sit too long or it will fall apart. The bread should feel moist but not soggy.
Cook until golden. Place the dipped bread into the hot skillet. Cook for 2–3 minutes per side, until golden brown with a slightly crisp edge. Adjust heat as needed so the toast doesn’t burn.
Serve warm. Transfer the cooked slices to a plate. Serve immediately with your favorite toppings like maple syrup, powdered sugar, or berries.