Cook the fettuccine noodles according to package directions, drain then set aside.
In a large skillet, heat the tablespoon of olive oil over medium heat. Add the sliced mushrooms to the skillet and cook for a few minutes until tender, then remove them from the skillet and set aside.
Add the salted butter to the same skillet you cooked the mushrooms in. Cook over medium-low heat until fully melted. Whisk in the flour and cook for 1 minute (whisking continuously.)
Add the chicken broth, heavy cream, parmesan cheese, and garlic powder; stir well.
Increase the heat to medium and bring the sauce to a gentle simmer for 1 minute. Reduce the heat to low and season with salt and pepper - to taste.
Stir in the spinach leaves and cook over low heat for 1 minute until it is starting to wilt.
Add the mushrooms and cooked fettuccine noodles. Stir well until all of the pasta is coated with the creamy sauce.
Serve immediately upon finishing. Enjoy!
Video
Notes
You can use grilled chicken, zucchini, squash, or sun-dried tomatoes in place of the mushrooms.