Ingredients
Scale
- 1 pound Fettuccine or Rigatoni pasta
- 2 large leeks (white and light green parts), thinly sliced
- 8 oz cremini mushrooms, sliced
- 4 tablespoons unsalted butter (divided)
- 1 cup (packed) Gruyère cheese, freshly grated
- 1/2 cup dry apple juice or vegetable broth
- 3 cloves garlic, minced
- 1 teaspoon fresh thyme leaves (or 1/2 tsp dried)
Instructions
- Step 1: Bring a large pot of salted water to a boil and cook the pasta according to package directions until al dente. Before draining, reserve 1 1/2 cups of the starchy pasta cooking water, then drain the pasta and set aside.
- Step 2: In a large, deep skillet or Dutch oven, melt 3 tablespoons of the butter over medium-low heat. Add the sliced leeks and cook slowly for 12–15 minutes, stirring occasionally, until they are very soft, deeply golden, and caramelized.
- Step 3: Increase the heat to medium, add the remaining 1 tablespoon of butter, the sliced mushrooms, and thyme. Cook for 5–7 minutes until the mushrooms are browned. Stir in the minced garlic for 1 minute until fragrant, then pour in the white grape juice with vinegar (or broth) and scrape up any browned bits from the bottom of the pan.
- Step 4: Reduce the heat to low. Add the reserved pasta water to the skillet. Bring to a gentle simmer, then add the cooked pasta, tossing well to coat. Season generously with salt and pepper.
- Step 5: Remove the skillet from the heat. Gradually sprinkle in the grated Gruyère cheese, stirring constantly until the cheese has melted and emulsified into a creamy, glossy sauce. Serve immediately.
Notes
- For the best creamy texture, ensure the heat is completely off before stirring in the Gruyère; adding it gradually prevents the cheese from seizing or clumping.
- Store leftovers airtight in the refrigerator for up to 3 days, but note the cheese sauce will absorb moisture and become very tight once chilled.
- To reheat, use a skillet over low heat and add a splash of milk or broth (about 1–2 tablespoons per serving) while stirring gently until the sauce returns to a creamy consistency.
- Serve this deeply flavorful pasta alongside a simple peppery arugula salad dressed lightly with lemon vinaigrette to cut through the richness of the cheese.
- Prep Time: 15 minutes
- Cook Time: 20 minutes
- Method: Stovetop
- Cuisine: American