This dish has a flavor so exquisite that it defies this very simple preparation. Once people taste these clams, they can never get enough. We have served this appetizer at Summer Shack since the day we opened and it is still one of our very best sellers. Grilled Clams are best made with small, special count littlenecks (about 1 1/2-inches wide). It's really easy, you put the clams directly over the hot fire and as soon as the shells pop open, you must take them off the grill or they will burn right through the shells. Place them right onto a bed of rock salt to hold them steady and spoon a few drops of sauce on each clam. If you are using a Great Grate, you can just remove the grate; no rock salt is needed. For equipment you will need a grill, grill brush and a pair of long tongs. The "Great Grate" is optional, but makes the job much easier.
Scrub and rinse the clams. Keep refrigerated until ready to use.
To make the sauce:
Melt 3 tablespoons butter in a 1-quart saucepan over low heat until it is foamy. Add the garlic and saute, stirring, until it is fragrant but does not color, about 30 seconds. Add the white wine and heavy cream, increase the heat to medium-high and reduce by half, about 8 minutes. Add the remaining butter 1 piece at a time, whisking constantly, until the sauce is shiny, emulsified, and thick enough to coat the back of a spoon. Remove the saucepan from the heat. Add the chives and season with salt and pepper. Keep the sauce warm until ready to serve.
Set up the littleneck clams on the grill or Great Grates or place them directly on the grill. Cook the clams without turning them. As soon as the clams pop open, after 8 to 10 minutes, transfer them carefully with tongs to a platter (or plates) of rock salt. If you are using a Great Grate, this won't be necessary. Use the tongs to pry off the top shells. Spoon 1 teaspoon sauce over each clam and serve immediately.