*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
**Nutrient information is not available for all ingredients. Amount is based on available nutrient data.
(-)Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.
Trim ends from zucchini and half each length-wise. Scoop out flesh of zucchini; dice. Arrange zucchini shells into a baking dish.
Heat olive oil in a 10-inch skillet over medium heat. Cook and stir onion, mushrooms, and garlic in hot oil until the onion is tender, 5 to 7 minutes; season with salt and pepper.
Stir diced zucchini flesh into the onion mixture; cook and stir until hot, about 5 minutes. Spoon zucchini mixture into the shells in the baking dish; top each with 1 tablespoon each feta cheese and Parmesan cheese.
Bake in preheated oven until the zucchini shells are soft, 30 to 40 minutes.