1. Line a cookie sheet with Gefen Parchment Paper.
2. Place diced onion on one side of the cookie sheet. Leave a space for the London broil. Place the mushrooms in the pan, then the sweet potato.
3. Drizzle oil and soy sauce over the vegetables. Add salt, pepper, and garlic and gently massage into each food section.
4. Bake at 400 degrees Fahrenheit for 30 minutes. Remove from oven.
5. Raise oven temperature to 500 degrees Fahrenheit. Place the London broil between the onions and the mushrooms and bake for 10–15 minutes, depending how well done you like your meat.