1. Boil salted water in a large pot and cook spaghetti until al dente according to the package instructions. Reserve some pasta water before draining.
2. In a large skillet over medium-high heat, heat olive oil and 2 tablespoons butter until melted. Add half of the minced garlic and sauté for about 30 seconds to 1 minute until fragrant.
3. Add the shrimp in a single layer without overcrowding; season with paprika, salt, and black pepper. Cook for about 1 to 2 minutes on each side until shrimp just start to turn pink.
4. Stir in the halved grape tomatoes (or fresh chopped tomatoes), chicken broth, Italian seasoning, crushed red pepper flakes (if using), and the remaining minced garlic. Cook for about 5 minutes until the tomatoes begin to soften and break down slightly.
5. Add fresh spinach to the skillet and reduce heat to medium. Cook for another 3 to 5 minutes, stirring occasionally, until the shrimp are fully pink and opaque, and the spinach is wilted.
6. Toss the drained spaghetti into the skillet with the shrimp and tomato mixture. Add a splash of reserved hot pasta water if a looser sauce is desired. Stir gently to combine all ingredients evenly.
7. Remove from heat and finish with the juice of half a lemon (optional), remaining butter (optional), and half of the grated Parmesan cheese. Stir to combine.
8. Serve garnished with the remaining Parmesan cheese and additional cracked black pepper or crushed red pepper flakes if desired.