Preheat oven to 375F. Spray a 9 x 13 inch casserole dish with cooking spray.
Heat olive oil in a skillet over medium heat. Sauté red pepper, zucchini and tomatoes for 4 to 5 minutes until just tender. Spread vegetables in the greased dish.
Whisk eggs with oregano, salt and pepper. Pour over the vegetables and top with olives and feta.
Bake for 35 to 40 minutes until set. Let stand for 5 minutes before slicing.
Notes
Tip: You can add spinach or swap vegetables to use what you have on hand.