Cook the pasta in a large pot of well-salted boiling water according to package directions for al dente. Drain; but reserve about ½ cup of the pasta cooking water to use for the sauce later.
While the pasta cooks, cook the bacon in a large skillet or Dutch oven over medium heat until crisp, about 5-6 minutes. Remove the bacon to a paper towel-lined plate, reserving 1 tablespoon of drippings in the pan. Coarsely crumble or chop the crispy bacon once it’s cool enough to handle.
Add the onion to the bacon drippings in the pan. Sauté until the onion softens, about 3 minutes. Stir in the sundried tomatoes and garlic; cook for 1 minute. Add the wine, broth, and basil. Simmer until the liquid reduces by about half, approximately 5 minutes. Add the cream and Parmesan cheese. Simmer gently, stirring regularly, until the sauce reduces and thickens slightly, 3-5 minutes. Taste and season with salt and pepper.
Reduce the heat to low. Add the cooked pasta, crumbled bacon, and spinach to the cream sauce. Gently stir until the sauce coats the pasta and the spinach wilts. Gradually add a little bit of the pasta cooking water to loosen up and thin the sauce until it reaches the desired consistency. Taste and season with salt and pepper, if desired.
Garnish with additional Parmesan cheese, fresh herbs, and crushed red pepper flakes just before serving.