salt & pepper
tomato for garnish if desired
For just myself for lunch I use an 8 inch cast iron skillet, enough slices of zucchini to make 2 layers and 3 eggs. (Yes, I'll probably die from high cholesterol, but so far so good... and I don't eat 3 eggs every day) If you have a mind to share your frittata (to each his own!), cut it into wedges like a pie and serve.
Heat your pan on medium. layer slices of zucchini, salt lightly and cover with lid. Cook about 5 minutes or until they appear tender. Beat eggs in a bowl, salt, and pour over zucchini. Lift the bottom slices of zucchini with a fork to let the egg run under. Put lid on, turn heat down to medium low, and cook until egg is mostly set. If you need to, turn on the broiler in your oven & set the pan under that for a minute or two to finish setting the tops of the egg. Slide frittata out onto a plate, top with tomatoes if desired. Cheese would be a good topping as well, but I prefer mine without.
There are so many vegetables that would be good in this... potatoes, onion, spinach or chard, broccoli. Your imagination is your limit. (or possibly your kids are your limit if you have picky ones like a couple of mine :) )