Cut zucchini in half lengthwise and scoop out the centers, leaving a 1/4-inch thick shell.

Chop the scooped-out zucchini pulp.

Place the zucchini shells in a 13x9-inch baking dish.

Sauté the chopped zucchini pulp, mushrooms, onion, and celery in 1 tablespoon of olive oil in a large skillet over medium heat for 3 minutes, or until tender.

Remove the vegetable mixture from the skillet.

In the same skillet, cook the creamy wheat cereal in the remaining 1 tablespoon of olive oil for 2 to 3 minutes, or until golden brown.

Reduce the heat to low.

Stir in the vegetable mixture, chicken broth, thyme, and black pepper; cover and cook for 5 minutes.

Remove from heat and stir in the egg product.

Spoon the mixture evenly into the zucchini shells.

Bake in a preheated oven at 350°F (175°C) for 20-25 minutes, or until heated through.