Step 1: Prepare the bread. Lay out each slice of bread on a clean surface. Using a rolling pin, flatten each slice firmly until it is thin and compressed. This makes it easier to roll without tearing.
Step 2: Spread the Nutella. Evenly spread about 1 to 1.5 teaspoons of Nutella over one side of each flattened bread slice, leaving a small margin around the edges.
Step 3: Roll them up. Starting from one short end, carefully and tightly roll each bread slice into a log shape. Pinch the seam gently to seal it. Set aside.
Step 4: Prepare the egg mixture. In a shallow dish or pie plate, whisk together the eggs, milk, vanilla extract, 1/4 teaspoon cinnamon, and a pinch of salt until well combined.
Step 5: Prepare the cinnamon sugar. In a separate shallow dish, combine the 1/4 cup granulated sugar and 1 teaspoon cinnamon. Mix well and set aside.
Step 6: Heat the pan. Melt unsalted butter in a large non-stick skillet or on a griddle over medium heat. Ensure the butter is fully melted and lightly sizzling but not burning.
Step 7: Dip and cook. Quickly dip each Nutella roll up into the egg mixture, ensuring all sides are coated but not overly soaked. Place them seam-side down in the hot skillet. Cook for 2-3 minutes per side, rotating until all sides are golden brown and the Nutella inside is warm and slightly gooey.
Step 8: Coat with cinnamon sugar. Immediately after removing the cooked roll ups from the pan, roll each one in the prepared cinnamon sugar mixture until evenly coated.
Step 9: Serve. Serve your warm Nutella French Toast Roll Ups immediately with your favorite toppings like powdered sugar, maple syrup, or fresh fruit.