Begin by laying one slice of crustless bread on a clean, flat surface. Using a rolling pin, gently roll the bread until it is as thin as possible, aiming for a thickness of about 1/16 to 1/8 inch. Roll in multiple directions to ensure even flattening. Repeat this process with all slices of bread, as achieving the right thickness is essential for rolling tightly without tearing.
Next, position a slice of cheese (or a neat line of shredded cheese) along one edge of the flattened bread, leaving a small border of approximately 1/4 inch on the sides. If desired, sprinkle optional seasonings like paprika or herbs over the cheese at this stage.
If you are using softened butter, gently spread a thin, even layer of it over the entire surface of each roll-up. This step can be delicate but will yield great results.
Carefully place the buttered roll-ups seam-side down in a preheated skillet. It may be necessary to cook them in batches to prevent overcrowding the pan, which could lower the temperature and result in less crispy roll-ups.
Cook the roll-ups for 2-4 minutes on the first side, or until they are golden brown and crispy.
Using tongs, gently turn the roll-ups to cook on another side. Continue to cook and turn for approximately 1-2 minutes per side until all sides are golden brown and crispy, and the cheese inside is fully melted and gooey. This process typically takes a total of 5-8 minutes. Don't worry if some cheese oozes out; it's perfectly normal and will create tasty, crispy cheese bits on the outside!
Serve the roll-ups immediately while they are hot, the bread is crispy, and the cheese is at its meltiest. Enjoy!