01 - Bring a large pot of salted water to a boil. Cook pappardelle according to package directions until al dente. Reserve 1/2 cup pasta water before draining.
02 - Heat olive oil and 2 tbsp butter in a large skillet over medium-high heat. Add sliced mushrooms and cook until golden brown and moisture has evaporated, about 7–9 minutes.
03 - Stir in shallot, garlic, and red pepper flakes. Cook for 1–2 minutes until fragrant, being careful not to burn the garlic.
04 - Pour in white wine or vegetable broth, scraping up any browned bits from the bottom of the skillet. Simmer for 1–2 minutes until slightly reduced.
05 - Reduce heat to medium. Add remaining 1 tbsp butter, thyme, and parsley. Season with salt and black pepper, stirring to combine.
06 - Add drained pappardelle to the skillet. Toss gently, adding reserved pasta water as needed to create a silky, cohesive sauce.
07 - Remove from heat. Fold in Parmesan cheese and lemon zest. Taste and adjust seasoning if necessary. Serve immediately with extra Parmesan and fresh parsley.