Fire up the grill and build a two-zone fire by loading your charcoal chimney full and letting it rip until the coals are fully ashed over and glowing orange - about 20 to 25 minutes. Spread the coals evenly for direct high heat across the entire grate. You are targeting 450 to 500 degrees Fahrenheit at the grate level. If you are on a gas grill, crank all burners to high and let it preheat with the lid closed for 10 to 15 minutes. Clean the grates thoroughly with a wire brush - you want clean metal for this cook.

While the grill is preheating, prepare your garlic butter compound. In a small bowl, combine the softened unsalted butter, minced garlic, chopped parsley, lemon juice, lemon zest, hot sauce, kosher salt, and cracked black pepper. Mix thoroughly with a fork until everything is fully incorporated and the butter is smooth. If you are going the New Orleans charbroiled route, stir the grated Parmesan in now as well. Set this aside at room temperature so it stays workable - do not refrigerate it at this point.

Scrub the outside of each oyster shell under cold running water with a stiff brush to remove any mud, grit, or debris. This matters because those shells are going directly on your grates and you do not want grit falling into your food. Set the cleaned oysters on a rimmed baking sheet and carry them out to the grill station. Work in batches if your grill surface requires it - do not crowd the grates.

Now comes the shucking. Put on your cut-resistant glove and grip each oyster flat-side up with the hinge pointing toward you. Insert the tip of your oyster knife into the hinge point and apply firm twisting pressure until you feel the hinge give way. Slide the knife along the top flat shell to sever the adductor muscle, then remove and discard the top flat shell entirely. Run the knife underneath the oyster meat to free it from the bottom cup shell but leave the oyster sitting in the cup shell in its natural liquor. This is called serving them on the half shell. Repeat for all 24 oysters.

Place each half-shell oyster directly on the hot grill grates, cup side down, making sure they sit level enough to hold their liquor. You should hear an immediate sizzle - that is exactly what you want. Work quickly and get them all on the grate within 60 to 90 seconds. Close the grill lid and let them cook for 4 to 5 minutes. You are looking for the natural oyster liquor in the shell to start bubbling and the very edges of the oyster meat to just begin to curl and firm up. That is your visual cue that they are nearly there.

Working quickly with your long tongs and heat-resistant gloves, drop approximately one teaspoon of the garlic butter compound directly into each oyster shell right on top of the meat. Close the lid and cook for another 60 to 90 seconds until the butter is fully melted and sizzling in the shell and you can see it starting to caramelize slightly around the edges. If you added Parmesan to your butter, you will start to see the faintest golden color developing - that is the sweet spot. Total cook time should be right around 5 to 6 minutes from when the oysters first hit the grates.

Using tongs and a folded kitchen towel or grill gloves, carefully transfer the oysters to a serving platter or keep them right on the rimmed baking sheet - just be careful not to spill that beautiful garlic butter out of the shells. Squeeze fresh lemon juice over the top of the whole platter and finish with an extra scattering of fresh chopped parsley. Serve immediately with thick slices of grilled crusty French bread on the side for soaking up every last drop of that smoky garlic butter. These do not wait - get them to the table and get people eating.