Bring a large stock pot of salted water to the boil. Cook the fettuccini per the instructions or until al dente, usually 10 minutes. Be sure not to overcook, as you will add pasta to the sauce mixture.
While the pasta is cooking, heat the olive oil in a large skillet over medium heat and add the garlic. Sauté for a couple of minutes until the garlic is golden and fragrant.
Add in the ricotta and milk until it forms a sauce. Turn the heat to low and let simmer.
Once the fettuccini is cooked to al dente, add it to the ricotta milk mixture.
Add the cooked pasta to the large skillet with the ricotta sauce. Tongs work well when combining the pasta with the sauce mixture.
Squeeze any excess liquid from the spinach and add it to the large saucepan with the pasta.
Using tongs, combine the spinach with the pasta. Stir to combine and coat the pasta.
Add a little chicken or vegetable stock to the pasta if the sauce seems too thick. Toss to combine and coat the pasta.
Top with your favorite garnishes and serve immediately.