Pat the shrimp dry and season both sides with salt and pepper.

Heat olive oil and 1 tbsp butter in a large skillet over medium-high heat. Sear shrimp in a single layer for about 2 minutes per side until pink and curled into a loose “C.”

Reduce heat to medium-low. Add remaining butter, garlic, and pepper flakes. Cook, stirring, for 30 seconds until fragrant. Off heat, squeeze in juice from half the lemon, then add the zest and parsley. Spoon sauce over shrimp and serve immediately.