Saute shallots in a half-stick of butter for about two minutes.
Add the Champagne and bring it to a boil. Lower the heat to a simmer and add the grouper and the scallops. Season with salt and pepper. Poach the fish and scallops in the Champagne for about eight minutes, covered. Remove seafood and keep warm.
Raise the heat to medium and reduce the liquid in the pan by half, uncovered. Add the cream and reduce by half again.
While that's going on, in a separate skillet saute the fennel and leeks in a half-stick of the butter. Season with salt and pepper.
Steam or poach the asparagus till crisp-tender. Rinse in cold water to stop cooking.
After the second reduction of the sauce, remove from heat and whisk in the last of the butter.
To serve, place the sauteed fennel and leeks in the center of a large plate. Pour some sauce around the plate, covering the entire bottom. Separate grouper into flakes about 1/4 inch thick. Slice scallops to the same thickness. Alternate grouper and scallops around plate. Top each with a little caviar. Place asparagus tips on top of the leeks and fennel, with the tips meeting in the center. Or, if all this is a little too Martha for you, just throw everything on the plate and nap it with the sauce.