Preheat oven to 425 degrees Fahrenheit (220 degrees Celsius).

Lay mushrooms on a baking sheet lined with Gefen Parchment. Drizzle with one tablespoon olive oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper.

Roast for 20 minutes or until cooked through and fragrant.

Preheat a heavy-bottomed frying pan over medium heat. Heat one tablespoon olive oil. Sauté onion until medium brown; then add zucchini, along with 1/2 teaspoon salt and 1/4 teaspoon pepper. Sauté another 10 minutes or until cooked but not mushy. Transfer vegetables to a plate.

Heat remaining one tablespoon oil, then add the ground veal, one teaspoon salt, and 1/2 teaspoon pepper. Brown until fully cooked and juices run clear, about 10 minutes. Add vegetables back to the meat, and add teriyaki sauce. Cook another two minutes until flavors meld.

Place the mushrooms on a platter, then spoon the meat mixture over them.