In a large pot of salted boiling water, cook the pasta according to package instructions until al dente. Drain and set aside, reserving about 1/2 cup of the pasta water.
In a large skillet, heat olive oil over medium heat. Add the chopped onion and cook until translucent, about 3-4 minutes. Stir in minced garlic and cook for an additional minute.
Increase the heat to medium-high and add the ground beef. Season it with salt, pepper, and Italian seasoning. Cook until well browned and cooked through, breaking it apart with a spatula, about 5-7 minutes.
Pour in the beef broth and heavy cream, stirring to combine. Bring the mixture to a simmer and allow it to cook for 3-4 minutes, letting it thicken slightly.
Stir in the spinach and cook until wilted (if using fresh) or heated through (if using frozen). Add the grated Parmesan cheese, stirring until melted and creamy. If the sauce is too thick, add a little reserved pasta water until the desired consistency is reached.
Add the cooked pasta to the skillet, tossing it well to coat in the creamy sauce. Adjust seasoning with more salt and pepper if needed.
Plate the creamy ground beef pasta in bowls and top with fresh basil leaves if desired. Serve immediately.