01 - Bring a large pot of salted water to a boil and cook pasta according to package instructions until al dente. Reserve ½ cup pasta water, then drain and set aside.
02 - Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook, breaking it up with a spoon, until browned and cooked through, about 5–6 minutes. Drain excess fat if necessary.
03 - Add diced onion to the skillet and sauté for 2–3 minutes until translucent. Stir in garlic and cook for 30 seconds until fragrant.
04 - Mix in chopped sun-dried tomatoes and cook for another minute.
05 - Pour in the beef or chicken broth and bring to a simmer. Let reduce by half, about 3 minutes.
06 - Reduce heat to medium-low. Add heavy cream, parmesan cheese, Italian herbs, and red pepper flakes. Stir until cheese is melted and sauce is creamy, about 2–3 minutes.
07 - Add cooked pasta and baby spinach (if using) to the skillet. Toss to coat, adding reserved pasta water as needed for desired consistency. Season with salt and pepper to taste. Serve hot, garnished with extra parmesan and fresh basil if desired.