Oysters in Champagne Sauce

Trim, wash, and blanch spinach. Squeeze dry; set aside. Shuck oysters, then place in a medium saucepan with oyster liquor, cover, and simmer over medium-low heat until oysters are opaque and slightly firm, 1-3 minutes. Remove oysters with a slotted spoon. Strain liquor through a fine sieve, return to pan, and set aside.

Wash and dry half the shells; discard the rest. Pour about 1⁄2'' rock salt onto 4 or 6 ovenproof plates; divide shells between plates, arranging them in a circle in the salt on each plate.

Bring champagne to a boil in a small saucepan over medium-high heat. Cook until reduced by half, 8-10 minutes, then set aside to cool.

Add fish stock to oyster liquor. Bring to a boil over medium-high heat, cook until almost syrupy, 12-15 minutes, then add cream and cook, stirring, until reduced by two-thirds, 10-12 minutes.

Transfer reduced champagne to the top of a double boiler over simmering water over medium-low heat. Whisk in egg yolks and cook until thick and shiny, about 5 minutes. Remove from heat and fold in stock mixture. Season to taste with salt and pepper.

Preheat broiler. Spread a thin layer of spinach in each shell and top with 1 oyster and 1-2 tbsp. sauce. Broil for 3-5 minutes. Serve hot.