For this hearty vegetarian dish, the pasta is cooked directly in the sauce, so there's no need to boil water in a separate pot. Japanese miso may seem an unlikely ingredient to pair with Italian pasta, but it deepens the mushrooms' earthiness, and lightly browning the miso as we do here develops even more flavor intensity so the dish tastes surprisingly meaty and rich. We particularly liked cavatappi because its twisty shape is a good match for the chunky mushrooms, but any short pasta shape, such as penne or fusilli, works well, too.