Pat shrimp dry and season with salt and pepper. Mince garlic, chop parsley, and juice the lemon.
Heat olive oil and half the butter in a large skillet over medium-high heat. Add shrimp in a single layer and sear 1–2 minutes per side until opaque. Transfer shrimp to a plate.
Reduce heat to medium, add garlic and red pepper flakes, sauté 30–45 seconds. Pour in broth and scrape up browned bits; reduce by half.
Stir in remaining butter and lemon juice until glossy. Return shrimp to the pan, toss to coat, heat through, and finish with parsley. Serve immediately.
Notes
Dry the shrimp well before cooking to ensure a good sear.
Reheat gently with a splash of broth to prevent rubbery shrimp.