Ingredients
Salt
2 tablespoons olive oil, plus more as needed
2 medium leeks, trimmed, white and light green parts thinly sliced (about 2 cups)
1 1/2 pounds mushrooms (such as cremini, shiitake and/or oyster mushrooms), stemmed and sliced
1 pound short pasta, such as ziti or cavatappi
2 tablespoons white miso
3/4 cup grated Parmesan, plus more for garnishing
1 tablespoon sherry or red wine vinegar, plus more to taste
1 tablespoon chopped parsley leaves and tender stems
Directions
1
Bring a large pot of salted water to a boil.
2
Meanwhile, heat 2 tablespoons oil in a Dutch oven or deep 12-inch skillet over medium-high until shimmering. Add the leeks, season with salt and cook, stirring often, until softened, about 5 minutes. If they look dry at any point, add a drizzle of oil.
3
Add the mushrooms to the leeks, season lightly with salt, and cook, stirring every 2 minutes, until the mushrooms have browned, about 10 minutes. (If they are done before the pasta, then adjust the heat to low.)
4
When the water is ready, add the pasta and cook until al dente. Halfway through the cooking process, reserve 1 cup of water and let cool slightly on the counter. Drain the pasta in a colander and drizzle with olive oil if done before the mushrooms.
5
When both the mushrooms and pasta are done, stir the miso into the reserved pasta water until mostly dissolved. Add it to the Dutch oven or skillet over medium-high heat along with the pasta, cheese and vinegar, stirring vigorously until a cheesy sauce forms and coats the noodles, 1 to 2 minutes. Remove from the heat and season to taste with more vinegar if needed.
6
Garnish with the parsley and more cheese; serve with a final drizzle of oil.