Use your waffle iron to make this tasty take on ham and cheese sandwiches.
Heat an 8-inch Belgian waffle iron. Open the croissants on a work surface. Pile the prosciutto, arugula and cheese on the bottoms. Close the sandwiches, pressing them to flatten. Cook 1 sandwich at a time: Add the sandwich to the waffle iron. Close the top onto the sandwich without locking it. Let cook on medium, pressing down on the waffle iron occasionally, until crispy on the outside and the cheese is melted, 4 to 5 minutes. Repeat with the remaining sandwiches.