Cook the spaghetti according to package directions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add garlic and cook for 1 minute until fragrant.
Stir in the sun-dried tomatoes and cook for another 2 minutes.
Pour in the cream and chicken broth. Stir well and let the sauce simmer for 5 minutes.
Add Parmesan cheese and stir until melted into the sauce.
Toss in the spinach and let it wilt, about 1–2 minutes.
Season with salt, pepper, and red pepper flakes if using.
Add the cooked spaghetti into the skillet and toss until coated in the sauce.
Serve warm, with extra Parmesan if desired.