Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta and set aside.

While the pasta is cooking, heat a large skillet over medium-high heat. Add 2 tablespoons of olive oil and 2 tablespoons of butter.

Once the butter is melted and bubbling, add the minced garlic and red pepper flakes. Sauté for about 1 minute, or until the garlic is fragrant but not browned.

Add the shrimp to the skillet in a single layer. Season with salt and black pepper. Cook for about 2-3 minutes on each side, or until the shrimp are pink and opaque.

Reduce the heat to low, then add the cooked pasta to the skillet. Pour in the reserved pasta water and the remaining 2 tablespoons of butter. Toss everything together until well combined.

Finish by stirring in the lemon juice and chopped parsley. Adjust seasoning with more salt and pepper if needed.

Serve immediately with grated Parmesan cheese on top if desired.