Whisk the custard. In a shallow bowl wide enough for a slice of bread, whisk the eggs, milk, vanilla, sugar, cinnamon, and salt until smooth, with no visible streaks of egg white.

Warm the pan. Set a large non-stick skillet or griddle over medium-low to medium heat. Melt a little of the butter; it should foam gently without smoking or browning rapidly.

Dip the bread. Dip each slice individually, turning to coat both sides. For many ¾-inch slices, about 5–15 seconds per side is a useful starting range. Dip soft, fresh bread for less time; drier, sturdier bread may need longer. Lift the slice while it still holds its shape, and let excess custard drip back into the bowl.

Cook a batch. Place the slices in the pan in one layer without crowding. Cook for about 3–4 minutes per side, adjusting the heat if the outside browns before the centre sets.

Check doneness and finish. The toast should be golden, with a set centre and no visibly wet egg mixture. A golden exterior alone does not confirm that the centre is cooked. When an internal temperature can be measured accurately, cook egg dishes to 160°F (71°C). Add more butter as needed and cook the remaining slices in batches.

Serve. Serve warm with optional maple syrup, berries, or confectioners’ sugar.