Zucchini Oven Frittata (low carb, vegetarian)

• 1 cup water
• 3 tablespoons olive oil
• 1/2 teaspoon salt
• 1/2 green bell pepper, seeded and chopped
• 3 zucchini, cut into 1/2-inch slices
• 2 cloves garlic, peeled   
• 1 small onion, diced
• 6 fresh chopped mushrooms
• 1 tablespoon butter
• 5 eggs
• salt and pepper to taste
• 1 cup shredded mozzarella cheese
• 3 tablespoons Parmesan cheese

1. Preheat oven to 350 degrees F (175 degrees C).
2. In a large skillet or sauce pan, combine water, olive oil, salt, green pepper, zucchini and garlic cloves. 
3. Simmer until zucchini is tender, about 5 to 7 minutes.
4. Drain off water and discard garlic. Stir in onion, mushrooms and butter. 
5. Cook until onion is transparent. 
6. Add eggs and stir; season with salt and pepper. 
7. Cook over low heat until eggs are firm.
8. Sprinkle mozzarella cheese over eggs. 
9. Bake in preheated oven for 10 minutes. 
10. Remove from oven and sprinkle with Parmesan cheese. 
11. Place under broiler for 5 minutes. Let stand 5 minutes before cutting into wedges and serving.