Everyday Food editor Sarah Carey shows you how to make a flavorful sauce for pasta in less than 25 minutes.
On a rimmed baking sheet, toss tomatoes with onion, oil, and red-pepper flakes; season, and top with pancetta. Roast at 450 degrees until tomatoes burst, 20 minutes, rotating pan once. Cook pound penne, reserving 1/4 cup pasta water. Toss penne with tomato mixture, parsley, and pasta water; season.