The alternating layers of cheese, when melted, hold everything together in a tidy package. Serve a vegetable on the side for a well-balanced meal.
Top a slice of bread with 2 cheese slices; top with 2 ham slices and another cheese slice. Arrange banana slices on top, and cover with 2 more cheese slices and bread. Repeat to make 4 sandwiches.
Melt butter in a large nonstick skillet over medium heat. Cook sandwiches in skillet until golden on one side. Flip, and cook until cheese has melted and bottom is golden brown. Serve warm.