In a bowl, stir together the ricotta, Parmigiano-Reggiano, thyme, parsley, lemon zest, salt, pepper and egg yolk. Put the egg white in a small bowl.

Using a 3-inch biscuit cutter, cut out rounds from the pasta sheets, spacing them as close together as possible; you should have at least 36 rounds.

Lay half the pasta rounds on a clean work surface and brush off any excess semolina flour. Using a pastry brush, brush the edges of the rounds with the egg white, then place a heaping 1 tsp. filling in the center. Top each with a plain pasta round and seal with your fingertips, pressing out any air bubbles. If desired, crimp the edges of the ravioli with the tines of a fork. Place the ravioli in a single layer on a baking sheet sprinkled with semolina flour.

In a large sauté pan over medium heat, warm the olive oil. Add the garlic and cook, stirring occasionally, until tender, about 2 minutes. Add the tomatoes and sauté, stirring occasionally, until they begin to blister and brown, 3 to 5 minutes. Season with salt and pepper, reduce the heat to low and keep the sauce warm.

Meanwhile, bring a large pot of salted water to a boil over high heat. Add the ravioli and simmer until tender, about 12 minutes. Using a slotted spoon, transfer the ravioli to the sauce, add the basil and stir to coat evenly. Serve immediately. Makes about 18 ravioli; serves 4.