Thaw the shrimp according to package directions. Then give them a fast rinse and drain.
While the shrimp is thawing, start your campfire. Lightly spray on cooking spray on half the grill. On the other half, cover it in foil. Then place the grill over the fire.
After shrimp is thawed, place on the non-foil side of grill char marks on your shrimp. Watch carefully and don't leave on too long because you don't want to overcook. Repeat to sear the other side of the shrimp.
Once they reach around 135 degrees Fahrenheit pull off the shrimp and place on the aluminum foil on the grill. Apply seasoning and butter and cover with a makeshift foil tent till shrimp are cooked.