Prepare all ingredients: peel and devein shrimp, mince garlic, wash spinach, and chop parsley.

In a large pot, bring salted water to a rolling boil. Add pasta and cook according to package instructions until al dente, about 8-10 minutes. Reserve 1/2 cup of pasta water, then drain the pasta.

In a large skillet, heat olive oil over medium heat. Add shrimp, season with salt, pepper, and red pepper flakes. Cook for 2-3 minutes on each side until pink and opaque. Remove shrimp and set aside.

In the same skillet, add more olive oil if needed and sauté minced garlic for 1 minute until fragrant. Add spinach and cook until wilted, about 2-3 minutes.

Return shrimp to the skillet, add drained pasta, and toss everything together. If the mixture seems dry, add reserved pasta water to achieve desired consistency.

Stir in lemon juice and grated Parmesan cheese. Adjust seasoning with salt and pepper to taste. Serve hot, garnished with chopped parsley.