Preheat a grill plate on high. Grill the Sadia Beef Burger Patties until cooked. Remove and cut into strips.
Meanwhile, heat the oil in a large fry pan; add the onion, capsicums and mushrooms and cook for 4-5 minutes, until softened. Add the sliced beef burger patties.
Preheat an oven grill. Slice each piece of bread through the middle, leaving a hinge, open up and grill until toasted. Lay a cheese slice on each toasted bread and return under the grill until the cheese melts.
Remove the bread from under the grill, top with the hot beef mixture and close to serve.