Bring a large pot of salted water to a boil, then cook the pasta until just al dente, about 8-10 minutes. Drain and set aside.
While the pasta cooks, heat olive oil and butter in a large skillet over medium heat until melted and fragrant, about 1 minute.
Add the sliced mushrooms to the skillet and sauté, stirring occasionally, until deeply browned and fragrant, about 8-10 minutes. They should be caramelized and tender.
Push the mushrooms to the side of the skillet, then add the minced garlic and cook for about 30 seconds until fragrant, stirring constantly to prevent burning.
Add the shrimp to the skillet in a single layer and cook for 2-3 minutes per side until they turn pink and opaque, with a slight jiggle in the center.
Pour in a splash of white wine or chicken broth if desired, letting it reduce for 2 minutes to concentrate flavors.
Add the cooked pasta to the skillet, tossing everything together to coat the noodles with the mushroom, garlic, and shrimp mixture. Let cook for 1-2 minutes to meld flavors.
Remove from heat, then stir in lemon juice, grated Parmesan, and chopped parsley if using. Toss to evenly distribute and enhance the flavors.
Serve immediately, garnished with extra Parmesan and herbs if desired. Enjoy the tender pasta coated in a savory, aromatic sauce with mushrooms and shrimp.
