Bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta cooking water before draining the pasta.

In a large skillet, heat the olive oil over medium heat. Add minced garlic and sauté until fragrant, about 1-2 minutes.

Add fresh spinach to the skillet and cook until wilted, about 2-3 minutes.

Once the spinach is wilted, reduce the heat and stir in the grated Parmesan cheese, mixing until melted and combined with the spinach and garlic.

Add the drained pasta to the skillet and toss to combine with the sauce. If the sauce is too thick, gradually add some of the reserved pasta water until the desired consistency is achieved.

Season with salt, black pepper, and red pepper flakes (if using) to taste. Mix well.

Serve the pasta immediately, garnished with chopped fresh parsley, if desired.