Bake the loaf according to the instructions on the package. When cool (and still wonderfully fresh) Cut off the ends and slice it. Remove the crust from each slice, leaving a square.
Roll each (crustless) square as flat as possible using a rolling pin.
Melt 3 tablespoons of the butter. Brush the top of the square with melted butter, sprinkle very lightly with garlic salt, then about 1 tablespoon of grated cheddar cheese onto the square of flattened bread. Roll up each one. Repeat with remaining slices.
Brush the outside of each roll with mayonnaise. (The mayonnaise helps the rolls to develop a crispy crust as they fry in the skillet!)
Melt 1 tablespoon butter in a non-stick skillet. Fry the rolls over medium-high heat, turning as needed to make them golden brown.
Serve the cheesy, crispy Soup Dunkers with a bowl of hot soup.
Makes about 10 Soup Dunkers.