Cook the pasta according to package directions. Drain and set aside.
Meanwhile, heat olive oil in a large skillet over medium-high heat. Add shrimp, season with salt and pepper, and cook until pink (about 2 minutes per side). Remove from skillet and set aside.
In the same skillet, add garlic and red pepper flakes (if using) and cook for 30 seconds until fragrant.
Pour in broth and lemon juice, scraping up any browned bits from the skillet. Simmer for 2 minutes.
Add cherry tomatoes and spinach. Cook until spinach wilts and tomatoes soften slightly, about 2-3 minutes.
Return shrimp to the skillet, add butter, and stir until melted and everything is combined.
Add the cooked pasta to the skillet and toss to combine. Adjust seasoning with more salt or pepper if needed.
Serve immediately, garnished with parsley and Parmesan if desired.