Bring a large pot of salted water to a boil and cook pasta according to package directions until al dente.
While pasta cooks, pat shrimp dry with paper towels and season generously with salt and pepper.
Melt 4 tablespoons of butter in a large skillet over medium-high heat.
Add shrimp to the skillet in a single layer and cook for 1-2 minutes per side until pink and opaque, then remove to a plate.
Reduce heat to medium, melt remaining 2 tablespoons butter in the same skillet.
Add minced garlic and red pepper flakes, sauté for 1 minute until fragrant.
Pour in chicken broth and lemon juice, bring to a simmer and cook for 2-3 minutes until slightly reduced.
Return cooked shrimp to the skillet along with any juices from the plate.
Drain pasta and transfer it directly into the skillet, tossing well to coat in the sauce.
Remove from heat, stir in Parmesan cheese and fresh parsley until melted and creamy.
Adjust seasoning with salt and pepper, then serve immediately with extra Parmesan on top.