Start by bringing a large pot of water to a boil. I always add a tablespoon of salt to enhance the pasta's flavor. Cook the pasta according to the package instructions until it is just under al dente. Remember, it will finish cooking in the sauce, so this is perfect.
While your pasta cooks, heat two tablespoons of olive oil in a large, deep skillet over medium heat. Add the minced garlic and cook until it becomes wonderfully fragrant, which usually takes about 1 minute.
Add the sliced mushrooms to the skillet, seasoning them generously with salt and pepper. Stir occasionally, allowing the mushrooms to cook until they turn golden and tender, approximately 8 minutes. This step is key for flavor!
Next, add the spinach to the skillet with the mushrooms. Let it wilt and beautifully meld into the mixture. It will seem like a lot at first, but it cooks down quickly.
Once the spinach has wilted, pour in the half-and-half and bring the mixture to a gentle boil. Reduce the heat and let it simmer until the sauce slightly thickens, which takes about 4 minutes.
Once your pasta is slightly undercooked, reserve about half a cup of the starchy pasta cooking water. Then, drain the pasta well.
Combine the drained pasta with the sauce in the skillet, along with the chopped parsley and grated Parmesan cheese. Toss everything together until it is well combined and coated in that luscious sauce.
Gradually add half of the reserved pasta water, continuing to toss the pasta until it is well coated and finishes cooking to perfection. If the sauce is too thick, feel free to adjust the consistency by adding more pasta water as needed.
Taste the dish and season with salt and pepper as desired. I always recommend tasting and adjusting to your preference.
Serve immediately, paired ideally with a light salad and crusty bread for a complete and satisfying meal. Enjoy every delightful bite!