Heat oven to 450° F. On a rimmed baking sheet, toss the tomatoes and garlic with the oil. Roast until the tomatoes burst, 8 to 10 minutes.
Meanwhile, cook the pasta according to the package directions. Drain, reserving ¾ cup of the cooking water.
Toss the pasta with the ricotta, parsley, and reserved cooking water. Season with ¾ teaspoon salt and ¼ teaspoon pepper.