Ingredients
Scale
- 2 tbsp olive oil
- 3 tbsp unsalted butter, divided
- 3 medium leeks — white + light green parts only, halved lengthwise and thinly sliced
- ½ tsp fine salt (plus more to taste)
- ½ tsp granulated sugar
- ⅓ cup dry sherry (or a splash of white wine)
- 8 oz oyster mushrooms (or substitute cremini/button/chanterelle), roughly torn or sliced
- 4 garlic cloves, minced
- 2 fresh sage leaves, thinly sliced
- ¾ cup heavy cream
- 1 tbsp balsamic vinegar
- 1 tsp lemon zest
- 1 lb fettuccine
- 1 cup reserved pasta cooking water (set aside when draining)
- ½ cup freshly grated Gruyère
- 1 tsp freshly ground black pepper
- ¼ cup toasted pine nuts, for finishing
Instructions
- Warm the olive oil and 2 tablespoons butter in a large sauté pan over medium heat. Add the sliced leeks, sprinkle with ½ teaspoon salt and the sugar, and cook gently, stirring occasionally, until they turn deep golden and sweet — roughly 18–22 minutes. If they begin to stick, splash in 1–2 tbsp water to loosen the fond.
- Pour in the sherry and let it bubble away until mostly evaporated and concentrated. Slide the leeks onto a plate and set aside.
- In the same skillet, add the remaining tablespoon of butter. Spread the mushrooms out in a single layer and leave them undisturbed for about 4 minutes so they brown nicely; flip and brown the other side. Season lightly with salt and pepper.
- Toss in the garlic and sage and cook just until fragrant, about 30–60 seconds. Return the caramelized leeks to the pan, then stir in the heavy cream, balsamic, and lemon zest. Bring the mixture to a gentle simmer and let it thicken slightly, 2–3 minutes. Taste and adjust seasoning.
- While the sauce reduces, cook the fettuccine in generously salted boiling water until al dente. Before draining, scoop out and reserve 1 cup of the starchy pasta water. Drain the pasta.
- Add the hot fettuccine to the sauce, pour in the reserved pasta water, then sprinkle in the grated Gruyère and the black pepper. Toss and simmer for a couple of minutes until the cheese melts and the sauce clings to the noodles. If the sauce seems too thick, add a splash more pasta water to reach the desired silkiness.
- Divide among four plates, scatter with toasted pine nuts, and serve immediately.
Notes
- Any meaty mushroom will work if oyster aren’t available — use what you have or combine varieties.
- To make ahead: prepare the leek–mushroom cream base through step 4, chill, and gently reheat before finishing with pasta and Gruyère.
- For extra brightness, finish with a squeeze of lemon juice just before serving.