Fry the pork loins with some oil in a pan. When done,remove them and keep them aside.
Fry the onion cut in thin slices together with some oil and the sugar.
Toast some bread slices and pour some oil over them. Place the pork loins on top, then the onion and finally cover it with an slice of melting cheese.
Place the toast in the oven to gratiné.
Serve it hot.