Butter a quiche dish or a pie plate and cover with crushed corn flakes (reserve some for top later). Chop onions and dice the zucchini. Saute them together in the butter until half cooked. Add cheese and mix well. Add salt and pepper and pour mixture into the quiche dish.
Beat the eggs until fluffy and pour over the zucchini mixture. Sprinkle a little of the corn flakes over the eggs.
Bake in a preheated 350 degree oven until the eggs are done or golden brown. Cut into wedges and serve while hot.