Using a serrated knife, carefully trim the crusts off each slice of bread. With a rolling pin, gently and firmly flatten each slice to about ⅛-inch thickness.

In a small bowl, combine the melted butter, brown sugar, and 2 tablespoons of cinnamon. Stir until a thick, sandy paste forms.

Spread a thin, even layer of the cinnamon mixture over each flattened bread slice, leaving about a ½-inch margin at the far edge.

Starting from the edge closest to you, roll each slice up tightly, pressing gently to seal the seam. Place the rolls seam-side down on a plate.

In a shallow bowl, whisk together the eggs, milk, vanilla, and the remaining ½ teaspoon of cinnamon until smooth and fully combined.

Place a large non-stick skillet or griddle over medium heat. Add 1 tablespoon of butter and let it melt, swirling to coat the pan.

Working with a few rolls at a time, dip each one into the custard, turning to coat all sides evenly. Allow any excess to drip back into the bowl.

Place the rolls seam-side down in the hot skillet. Cook for 2 to 3 minutes total, turning occasionally with tongs, until all sides are golden brown and slightly crisp.

Add more butter to the skillet between batches as needed.

Transfer the cooked roll-ups to a serving plate. Serve warm with maple syrup, a dusting of powdered sugar, or an extra drizzle of the cinnamon filling for dipping.