In a small bowl, combine the ricotta with some milk to thin it out to a spreadable consistency and season it with thyme, salt and pepper, to taste.
Line a cake pan with plastic wrap. Choose a nonstick skillet similar in size to your cake pan.
Beat the eggs with salt and pepper, to taste. Have 2 plates on hand that are similar in size to the skillet. Heat a tablespoon of extra-virgin olive oil in the skillet over medium to medium-high heat. Add 1/3 of the zucchini, chili, sweet peppers and scallions to the pan, season with salt and pepper, to taste. Saute the mixture for a couple of minutes then add 1/3 of the eggs and brown the omelet. Cover the pan with a plate and flip the omelet over and brown on the other side. Slide the browned omelet onto another plate and repeat twice more to create 3 omelets.
Put the most appealing omelet in bottom of a cake pan, spread with half the ricotta mixture and top with another omelet, more cheese and then the third omelet. Invert onto cake plate or stand and top with arugula and shaved Parmesan. Cut into wedges and serve.