Heat a 10-inch pan over medium heat. Add the oil. Saute the leeks until soft. Add the squash, zucchini, and potatoes. Cook until the vegetables soften about 5 to 7 minutes.
In a bowl whip eggs and half and half; stir in ricotta. Add the Parmesan, a pinch of salt, and a grind of pepper. Brush a new pan lightly with oil and place over medium heat. Add the egg mixture, then tomatoes, followed by softened squash potato mix. Cook until the eggs are firm.