Minced fresh cilantro, for garnish
Preheat the oven to 350°F.
Coat a sheet pan with the olive oil.
Combine the beef, egg, arrowroot powder, onion powder, oregano, thyme and garlic powder in a large bowl and mix thoroughly.
Roll the beef mixture out on the prepared sheet pan to 1⁄2-inch thickness. Be sure the thickness is consistent.
Bake the beef for 10 to 15 minutes, or until it is cooked through.
While the beef is baking, combine the diced tomatoes and tomato paste in a medium bowl.
Remove the beef “crust” from the oven and drain off the liquid.
Cover the “crust” with the tomato sauce, and then spread the garlic, mushrooms, onions, bell peppers and olives on top.
Sprinkle with salt and pepper, if desired, and continue baking for another 5 minutes, or until the veggies are cooked.
Remove the meatza from the oven, garnish with cilantro, allow to cool a bit and serve. NOTE: A rolling pin comes in handy for rolling out your meat.