Ricotta needs to drain for several hours (overnight is best). The salad can be served immediately but tastes better when it has rested an hour or so. Add crusty bread and white wine for a delicious lunch.
Put ricotta in a large sieve or colander lined with a double thickness of cheesecloth. Cover the ricotta with the cheesecloth, set the sieve or colander over a bowl to catch the draining whey, and set a plate with a weight on top of the ricotta to speed draining. Refrigerate for several hours or overnight.
Preheat the oven to 375°. Butter a 10-in pie pan. In a large bowl, stir together the ricotta and Parmigiano-Reggiano. Season to taste with salt and pepper. Stir in the eggs, beating well. Transfer the mixture to a prepared pan spreading it evenly. Bake in the upper third of the oven until puffed and lightly brown-55 minutes. Let cool, then unmold onto a cutting board.
In a large bowl, combine all the ingredients. Toss well. Taste and season according to personal preference. Serve immediately or let stand for up to 1 hour, tossing occasionally.
Cut the ricotta into 8 wedges and place on individual plates. Accompany each serving with some of the parsley salad.