Add the olive oil, vinegar, and salt and pepper to taste and toss to combine. Place the salad bowl on the table. Place the toasted burger buns on plates and place 1 burger on each bun. Serve the salad alongside. If you want to use a hard or semi-hard cheese like Gouda, grate it first.
Ground sirloin is more expensive than other types of ground beef.
Or, for a real change of pace, try ground pork or lamb. If you do not have a grill pan, cook these burgers in a 12-inch nonstick skillet, lightly sprayed before you preheat it with vegetable cooking spray. There is very little fat in ground sirloin and you will need the film of cooking spray to prevent the burgers for sticking. If you find you haven't cooked the burgers enough, place them back in the skillet and cook until done. If you cut the burgers open and place them in the microwave, the cheese will turn liquid and run out.