Cut the mushroom stalks even with the caps and slice 1/8-inch thick
Heat the butter in a 12-inch stainless steel sauté pan; add the mushrooms, and sauté on high heat, tossing all the time, until light golden brown.
Add the fish stock, wine, and salmon. Cover and gently simmer for 7 to 10 minutes until the salmon is cooked through. To check if it is ready, insert a small sharp knife into the thickest part of each fillet to check if it is cooked through. Be careful not to over-cook or the salmon will be dry.
Remove the salmon from the pan with a slotted spatula. Keep the fillets warm
On a high heat, reduce the pan juices to a light syrupy consistency. Add the cream and shredded basil and continue to reduce until the mixture is thick enough to coat a spoon. Add any juices that have accumulated from the salmon and continue to reduce for a minute more. Add salt and freshly ground pepper to taste.
Arrange the salmon on four dinner plates and spoon the sauce on top. Garnish each fillet with a basil leaf.