Thaw frozen tails in cold water for 30 minutes or overnight in the fridge. Butterfly each tail using kitchen shears — cut lengthwise through the top shell from the fleshy end toward the fins without cutting through the meat. Follow with a knife to cut through the meat, then fold open. Alternatively, split completely in half down the center. Brush exposed flesh with canola oil or melted butter, season with salt and pepper. Thread a skewer lengthwise through each tail to prevent curling. Preheat grill to medium-high and lightly oil the grates before cooking.

Place tails flesh-side down on a fully preheated medium-high grill. Cook undisturbed for 5–6 minutes until edges turn opaque and flesh begins pulling from the grates. Flip to shell-side down, baste generously with butter or sauce, and cook another 3–5 minutes, basting every minute. Total time: 8–12 minutes depending on tail size. Pull at 140°F internal (135°F is acceptable for a more tender result — carryover heat will finish the job). Use an instant-read thermometer in the thickest part of the meat; do not rely on shell color as a doneness indicator.

Pull tails at 135–140°F internal temp. Flesh should be opaque and slightly firm. Don't overcook — rubbery meat means they stayed on too long. No resting needed, but 1–2 minutes helps juices settle. Finish with fresh lemon juice and serve with herb, garlic, or clarified butter for dipping. Garnish with parsley, chives, or scallions if desired. Leftovers keep refrigerated in an airtight container for 2–3 days.