Step 1: Cook the Pasta : Bring a large pot of salted water to a boil. Add the fettuccine and cook according to package directions until al dente. Reserve ½ cup of pasta water, then drain and set aside.

Step 2: Sauté the Mushrooms : In a large skillet, heat olive oil and butter over medium heat. Add onions and sauté for 2–3 minutes until softened. Add garlic and cook until fragrant (about 30 seconds). Add mushrooms and cook for 6–7 minutes, stirring occasionally, until golden brown and their moisture evaporates.

Step 3: Add Spinach : Stir in the fresh spinach leaves and cook for 1–2 minutes until wilted. Season with salt and pepper.

Step 4: Make the Parmesan Cream Sauce : Reduce heat to low and pour in the heavy cream. Stir and let it simmer gently for 2–3 minutes until slightly thickened. Add grated Parmesan cheese and stir until melted and smooth. Add nutmeg (optional) for extra flavor.

Step 5: Combine Pasta and Sauce : Add the cooked fettuccine to the skillet with the sauce. Toss to coat, adding a splash of reserved pasta water if the sauce is too thick. Taste and adjust seasoning as needed.

Step 6: Serve : Plate the pasta and sprinkle with extra Parmesan and chopped parsley. Serve immediately while warm and creamy.