Fill a large pot with water, add a generous pinch of salt, and bring it to a boil. Add the spaghetti and cook according to the package instructions until al dente—usually about 8 to 10 minutes. Reserve a cup of pasta water before draining the spaghetti.
While the pasta cooks, heat 2 tablespoons of olive oil over medium heat in your skillet. Add the peeled and deveined shrimp, season lightly with salt and pepper, and cook for about 2 minutes on each side until pink and opaque. Remove shrimp and set aside.
In the same skillet, add minced garlic and red pepper flakes. Sauté for about 30 seconds until aromatic. Pour in crushed tomatoes, season with salt and pepper, and let simmer gently for 8 to 10 minutes until sauce thickens slightly.
Add the cooked spaghetti into the skillet with the sauce and toss well to coat. Add reserved pasta water if sauce is too thick to create a silky texture.
Return the cooked shrimp to the skillet and gently stir to combine. Sprinkle chopped fresh basil over the top and toss once more.
Divide the pasta among plates and finish with a generous sprinkle of grated Parmesan cheese. Optionally, drizzle a little more olive oil or add fresh basil leaves. Serve immediately.
