Sauté Garlic: Melt 2 tbsp butter and 2 tbsp olive oil in a large skillet over medium-high heat. Add minced garlic and red chili flakes; cook for 1 minute until fragrant.
Cook Shrimp: Add shrimp in a single layer. Cook for 3 to 4 minutes, stirring frequently, until shrimp turn pink and opaque. Transfer shrimp to a plate using a slotted spoon; set aside.
Reduce Sauce: In the same skillet with pan juices, pour in chicken broth and lemon juice. Bring to a simmer. Add remaining 2 tbsp butter and 2 tbsp olive oil, stirring until butter melts and sauce thickens slightly.
Combine & Season: Return cooked shrimp to the skillet. Toss for 1 minute to coat thoroughly in the garlic lemon butter sauce. Season with salt and black pepper to taste.
Garnish & Serve: Remove from heat, sprinkle generously with fresh chopped parsley, and serve immediately over cooked linguine or with warm crusty French bread.