Boil the pasta: Bring a large pot of salted water to a boil. Cook the pasta until just shy of al dente. Scoop out 1 cup of the starchy pasta water and set it aside. Drain the pasta.

Prep the pan: While the pasta cooks, heat a large skillet over medium-high. Add olive oil and 1 tablespoon butter.

Brown the mushrooms: Add the sliced mushrooms in a single layer. Let them cook undisturbed for 2–3 minutes to brown, then stir and cook another 3–4 minutes until they’re deep golden and their liquid has evaporated. Season with a pinch of salt and pepper.

Add aromatics: Reduce heat to medium. Stir in the shallot and cook 1–2 minutes until softened. Add the garlic, thyme, and red pepper flakes (if using). Cook 30–60 seconds until fragrant.

Deglaze: Pour in the white wine. Scrape up any browned bits from the pan. Simmer 1–2 minutes until the wine reduces by about half.

Create the sauce: Add the cream and the remaining 1 tablespoon butter. Stir until smooth and glossy. Season with salt and black pepper. If the sauce looks thick, splash in some pasta water.

Toss with pasta: Add the drained pasta to the skillet. Sprinkle in the Parmesan and toss until the sauce clings to the noodles. Add pasta water a little at a time until it’s silky and coats everything.

Finish and brighten: Turn off the heat. Stir in lemon zest and parsley. Taste and adjust salt, pepper, or lemon.

Serve: Twirl into bowls. Top with extra Parmesan. Add optional pancetta, toasted walnuts, or a light drizzle of truffle oil for a festive touch. Serve with lemon wedges.