Three favorite indulgences - oysters, champagne, and caviar - are com¬bined in this dish. The oysters are poached in their shells with champagne, napped with a champagne hollandaise, given a golden glaze under the broiler, and finished with a decadent dollop of caviar. The oysters emerge barely warmed through and more seductive than ever. We serve them on a bed of rock salt or blanched seaweed.

For the Champagne Hollandaise Sauce

1. Melt one pound of butter and keep warm.
2. Place the egg yolks, cornstarch (optional), champagne, and cold water in the top of a double boiler or in a stainless steel bowl.
3. Set the mixture over a pot of simmering water and whisk vigorously until the yolks begin to thicken.
4. Continue whisking until the yolks are pale yellow and very thick, about 6 to 8 minutes. Do not overcook, or the yolks may scramble.
5. Remove the yolks from heat and slowly begin to whisk in the warm butter.
6. Add all of the butter except for the milky residue in the bottom of the pan.
7. Whisk in the lemon juice, salt, paprika, cayenne, and white pepper. Keep the sauce covered in a warm (not hot) place.

Note: Hollandaise sauce can be held for several hours in an earthenware crock in a warm spot on the back of the stove or in a stainless steel canister resting in a water bath at 125 degrees. Be aware that if the sauce becomes too cold or too hot, it may separate.

For the Oysters

1. Scrub the oyster shells with a stiff brush under cold running water.
2. Using an oyster knife, pry open the oysters, discard the top shells, loosen the oyster from the bottom shell, and place the oysters on their half shells on a baking sheet. The oysters may be opened ahead of time and stored, covered, in the refrigerator for several hours.
3. Preheat the broiler to high.
4. Wash and stem the spinach. Melt the butter in a small skillet over medium-high heat.
5. Add the spinach, season it with salt, sugar, and pepper and sauté until it is just wilted.
6. Tuck a few leaves of wilted spinach under each oyster. Douse each oyster with a little champagne.
7. Place the oysters under the hot broiler for about 30 to 60 seconds, until they are warmed through. They should still look almost raw.
8. Completely nap each oyster with champagne hollandaise sauce and place them back under the broiler until the sauce is golden brown, rotating the baking sheet so that the sauce will brown evenly on each oyster.
9. Carefully transfer the hot oysters to serving plates, spoon a dollop of caviar on the center of each one (if desired), and serve immediately.