Bring a large pot of water to a rolling boil. Add 1 tbsp kosher salt and 1 tsp olive oil. Add 12 oz dried pasta and cook according to package instructions until just al dente (usually 8–10 minutes). Reserve 1 cup of pasta cooking water, then drain the pasta and set aside.

Mushroom sauté

Prepare ingredients

While the pasta cooks, clean and slice 18 oz mixed mushrooms and mince 1 large shallot and 3 cloves garlic. Measure out thyme, red pepper flakes, salt, and pepper.

Sauté mushrooms

Heat a large sauté pan over medium-high heat. Add 1 tbsp olive oil and 2 tbsp unsalted butter. When butter foams, add the sliced mushrooms in a single layer (work in batches if necessary to avoid steaming). Let them sear undisturbed 2–3 minutes, then stir and continue cooking 3–4 more minutes until golden and most moisture has evaporated.

Aromatics

Reduce heat to medium. Add the minced shallot and cook 1–2 minutes until translucent. Add the minced garlic, 1 tsp fresh thyme leaves, and 1 tsp crushed red pepper flakes. Cook, stirring, 30–45 seconds until fragrant. Season with 1 tsp kosher salt and 1/2 tsp freshly ground black pepper.

Sauce & finishing

Deglaze

Pour 1/2 cup dry white wine (or vegetable broth) into the pan to deglaze, scraping up browned bits from the bottom. Simmer until the liquid is reduced by about half (2–3 minutes).

Build sauce

Add 1/2 cup vegetable or chicken stock and bring to a gentle simmer. Stir in 3/4 cup heavy cream and simmer 2–3 minutes until sauce thickens slightly. Taste and adjust seasoning.

Combine with pasta

Add the drained pasta to the pan with the mushroom sauce. Toss to combine, adding up to 1 cup reserved pasta water a little at a time to loosen the sauce and achieve desired consistency.

Finish & serve

Remove pan from heat and stir in 3/4 cup finely grated Parmesan, 1 tbsp cold unsalted butter, 1 tsp lemon zest, 1 tbsp lemon juice, and 2 tbsp chopped fresh parsley. Toss until butter and cheese are melted and incorporated. Adjust salt and pepper to taste. Serve immediately, garnished with extra Parmesan and parsley if desired.