Make the sole: Lightly score the skin side of the sole fillet to keep the sole from the shrinking. Season sole with salt and pepper and brush with the melted butter. Turn sole on its side, and form a circle, skin side in, with the fillets. Secure with a toothpick. Place on a lightly greased non-stick baking tray. Refrigerate until needed.
Make the sauce: Combine the vegetable stock, ginger and lemon-grass. Reduce by half. Add heavy cream and butter. Season with salt and pepper. Strain sauce. Keep warm in a small saucepan.
Make the souffle: Combine sole fillet, egg yolk, whole egg, cream, salt and pepper. Puree until smooth. Whip egg whites until stiff peaks form. Fold egg whites into puree. Layer crab meat and souffle mixture into sole circles, starting with the crab. Use half an ounce of crabmeat total per sole fillet. Squeeze lemon juice over crab during layering. Place souffles in a preheated 375 degree oven for 7 minutes. Souffle should be golden brown. Assemble the dish: Using a spatula, carefully remove the souffle to a serving plate. Spoon sauce around edge of plate. Garnish each plate with three grapefruit segments and sprigs of chervil.