Arrange the shrimp in a circle around the pan. Get fancy with them. Or don't. Up to you.
Combine the butter, garlic, red pepper flake and Old Bay seasoning and drizzle over the top of the shrimp.
Squeeze the juice of 1/2 of the lemon over the top. Place the remaining half lemon in the center of the skillet.
Place skillet over indirect heat and cook 20-25 minutes. Check on the shrimp at least once. You might want to turn the skillet 180 degrees (USING A THICK OVEN MITT!) to get all sides cooked evenly. The shrimp are done when they are pink and the internal temperature has reached 145 F.
Remove skillet from grill USING A THICK OVEN MITT and sprinkle with parsley.
Squeeze the remaining lemon half (from the skillet) over the shrimp and serve.
Notes
Serve with garlic bread or toasted Texas toast for soppin'.