1. Brush onions and peppers with oil, sprinkle with salt and pepper to taste. Grill 6-9 minutes on medium low heat turning often until tender crisp.
2. Remove, slice onion, put both in a bowl, drizzle with balsamic vinegar, toss and set aside.
3. Salt and pepper beef strips and grill to desired doneness. Toss with vegetables and serve.
Tip: Use a grill basket or sheet of foil to ensure the items don’t fall through the grate.