Fire up your grill to high heat, targeting 400-450°F. Clean and oil the grates well - shrimp can stick easily. Thread 4-5 shrimp per metal skewer, piercing through both the head and tail sections so they lay flat. Pat shrimp completely dry with paper towels, then brush lightly with olive oil and season with salt and pepper.

While the grill heats, make your garlic butter by melting butter in a small saucepan over medium heat. Add minced garlic and cook for 1-2 minutes until fragrant but not browned. Remove from heat and stir in lemon juice and red pepper flakes. Keep warm but off direct heat.

Place skewers on the hottest part of the grill. Cook for 2-3 minutes without moving them - you want those char marks to develop. Brush the tops with garlic butter, then flip and cook another 2-3 minutes. The shrimp are done when they reach 120°F internal temp and have turned pink-orange with nice char marks.

Remove skewers from grill and immediately brush with remaining garlic butter. Let rest for 2-3 minutes to allow the butter to soak in, then garnish with fresh chopped parsley. Serve immediately while the garlic butter is still warm and the shrimp are at peak tenderness.