In a shallow dish, whisk together the milk, eggs, cinnamon, and vanilla extract until well combined. This will give the French toast its classic rich and custardy texture.

Spread 2 tablespoons of Nutella evenly over one slice of bread, then top with a second slice to create a sandwich. Press lightly to help it hold together.

Heat a nonstick skillet or griddle over medium-low heat. Add about 1/2 tablespoon of butter and let it melt, ensuring the surface is evenly coated.

Dip the Nutella sandwich into the custard mixture, letting it soak for about 5 seconds on each side. Be careful not to oversoak, or the bread may become too soft.

Place the soaked sandwich in the preheated pan and cook for 2-3 minutes on low heat, or until the bottom is golden brown. Flip carefully and cook the other side until equally golden.

Remove from the pan and serve warm. Dust with powdered sugar, drizzle with syrup, or add fresh berries for an extra special touch.