2 Tblsp unsalted butter
2 small shallots or garlic cloves, finely chopped or minced
1/3 C chardonnay or other white wine
1 C heavy (whipping) cream
pinch white pepper
2 dozen fresh oysters, shucked, 'bottom' shells (the rounded, cup-shaped side) reserved
2 lb box rock salt
Melt the butter over medium heat in a small saucepan. Add shallots or garlic and cook, stirring, until they are translucent and beginning to soften, about 2 minutes.
Add the chardonnay, bring to a lively simmer and reduce until only about 2 tblsp of liquid remains. Add the cream and bring to a boil.
Lower the heat to a simmer and reduce to 2/3 C. Remove from the heat stir in the white pepper and set aside.
Preheat the oven broiler to 500º. Arrange the top oven rack so an edged cookie sheet will fit below the element.
Prepare appetizer plates by placing a bed of rock salt on each to hold the oysters.
Distribute the rock salt evenly between edged cookie sheets large enough to hold the oysters.
If the fishmonger shucked your oysters return them to their cleaned shells one by one and add about 1/2 tsp of the oyster liquid to each, nesting the shells carefully in the rock salt so the contents don't spill. Otherwise, arrange freshly shucked oysters back on their half shell in the rock salt-filled cookie sheet ensuring that their liquid doesn't spill.
Spoon about 2 tsp of the cream mixture on top of each oyster, coating the oyster well without having the liquid overflow the shell.
Put the cookie sheet(s) in the oven and broil just til the liquid bubbles and the oysters' edges begin to curl.
Repeat for each pan.
Carefully lift 4 oysters in their shells onto each plate and serve immediately.