Preheat oven to 375ºF.
Place a large skillet over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Add the onion and garlic to the pan, and sauté until tender, 5-6 minutes. Add in the tomatoes, basil, some salt and pepper. Using a wooden spoon or potato masher, crush the tomatoes up to make a chunky sauce. Bring up to a simmer and reserve the sauce warm.
In a large mixing bowl, stir together the ricotta, parsley, egg yolk, Parmigiano Reggiano, some salt and pepper.