Cook the Pasta:
Bring a large pot of salted water to a boil. Cook pasta according to package directions. Reserve ½ cup pasta water, then drain and set aside.
Brown the Sausage:
Heat olive oil in a large skillet over medium-high heat. Add sausage and cook until browned, breaking it up as it cooks. Drain excess fat if needed.
Add Garlic and Tomatoes:
Stir in garlic and red pepper flakes. Cook for 1 minute until fragrant. Add sun-dried tomatoes and cook another minute.
Make the Sauce:
Reduce heat to medium. Stir in heavy cream and chicken broth. Simmer for 2–3 minutes, then add Parmesan and stir until melted and smooth.
Add Spinach and Pasta:
Stir in spinach and cook until wilted. Add cooked pasta and toss to coat, adding reserved pasta water a splash at a time to loosen the sauce if needed.
Season and Serve:
Taste and adjust with salt and pepper. Garnish with fresh herbs and extra Parmesan.