2 lb zucchini, cut into 1-inch dice
 1 medium onion, finely chopped
 2 Tbsp low sodium butter
 1 Tbsp olive oil
 salt
 pepper
 1 1/2 cup finely crushed crackers
 1 cup / 6 oz mozzarella cheese
 2 eggs, beaten
 1/4 cup Parmesan, grated
 
 Preheat the oven to 350.
 
 In a medium pan, heat butter and olive oil. Add chopped onions and cook
 until transparent. Then drop in zucchini dices, season everything with 
salt and pepper, and cook over medium heat, stirring occasionally, until
 vegetables are soft enough; for about 10-15 minutes. Then set aside and
 let them cool slightly.
 In the meantime, mix together crushed 
crackers and mozzarella cheese. Stir half of this mixture into the 
vegetables. Pour in beaten eggs, season generously with salt and pepper,
 and mix it thoroughly.
 Transfer the mixture into the baking dish 
and top with the remaining cheese and cracker blend. Coat with grated 
Parmesan and then bake for 25-30 minutes, until lightly browned and 
crispy on top. 
 Let the casserole stand for 5 minutes, then serve warm.