Wash the spinach and put the dripping wet leaves into a saucepan over low heat. Cover and let it cook until the leaves are limp. Remove the spinach leaves and stretch them out, trying not to tear them.
In a skillet, bring the white wine to a boil and poach the oysters in it for about two minutes. Drain and chop coarsely.
Lightly butter the insides of six six-ounce soufflé cups or ramekins. Drape the spinach leaves over the rims of the cups, so that they're half in and half out of the cups. Divide the chopped oysters among all the cups.
Mix the eggs, cream, Pernod, oyster water, nutmeg, salt and pepper in a bowl. Whisk until blended. Pour over the oysters in the cups. Fold spinach leaves over the tops of the cups.
Place the dishes in a pan of warm water. Bake at 325 degrees for 40 minutes.
While the flans are baking, make the sauce. Heat the wine to a boil and in it cook the shallots until all the liquid has been absorbed. Add heavy cream and reduce until thickened to sauce consistency. Whisk in butter, lemon juice, salt and pepper. Strain the sauce and keep warm.
Allow the soufflé dishes to cool for a few minutes after baking, then unmold onto serving plates. Spoon sauce over flans and serve.