Preheat oven to 400ºF.
Lay out the slices of bread and smoosh them down lightly with a rolling pin.
Lay some cheese and two leaves of basil down onto each slice and roll them up, pressing them with the seam down so they stay closed.
Brush the outside of each sandwich lightly with melted butter and transfer to a baking sheet. Bake until golden brown and the cheese has melted, 10-12 minutes. Serve with warm tomato sauce as a dipper alongside.