Begin by boiling a large pot of salted water. Add your fettuccine or spaghetti and cook according to the package instructions until al dente. Reserve about 1 cup of pasta water, then drain the pasta and set it aside.
In a large skillet, heat the olive oil over medium heat. Add the finely chopped garlic and sauté for about 1-2 minutes, or until fragrant. Be careful not to burn the garlic.
If using fresh spinach, add it to the skillet and sauté until wilted, about 3-5 minutes. For frozen spinach, add the puree directly to the skillet and stir until heated through.
Pour in the dairy-free cream and stir to combine with the spinach and garlic. Allow it to simmer gently for a few minutes.
Stir in the nutritional yeast and season with salt and pepper to taste. If the sauce is too thick, add a splash of the reserved pasta water.
Add the cooked pasta to the skillet and toss to coat evenly with the creamy spinach sauce.
Divide the pasta among plates and enjoy immediately, garnished with additional nutritional yeast or black pepper.
