1. Preheat the oven to 425 degrees F.
2. Combine all of the marinade ingredients in a medium sized bowl.
3. Add the pieces of beef (or other protein) to the marinade, and stir to coat.Separate the onion rings and form into two cones on a large baking sheet. (OR just toss the rings with the other vegetables before roasting.)
4. Combine the remaining vegetables on the same baking sheet.
5. Add the oil, salt, and pepper and stir to coat the vegetables.
6. Spread the vegetables out on the sheet and place in the oven.
7. Bake for 20 minutes.
8. Remove the pan from the oven and move the vegetables to one side to make room for the beef.
9. Add the beef to the pan, making sure the pieces are separated.
10. Pour the marinade over the beef.Return the pan to the oven and roast for another 8 minutes, or until the meat is cooked to your liking. Dont overcook or it will become dry and chewy.
11. Remove from the oven and stir the beef and vegetables together with the sauce.
12. Serve immediately over cooked cauliflower rice if desired.