In medium saucepan, combine wine, cream and shallot. Heat to boiling and cook at medium heat until reduced to 1/2 cup, about 10 minutes.
Reduce heat to low and whisk in 1 cup butter, 1 to 2 Tablespoons at a time. Season with pepper. Remove sauce from heat.
Add radish, dill and horseradish. If a slightly thicker sauce is desired, thicken with flour/water mixture. Set aside.
Set oven to broil. Line cookie sheet with foil. Rinse salmon fillets and pat dry; place on cookie sheet. Brush with olive oil. Broil until cooked through, turning once.
Remove salmon to plate and top with a generous portion of sauce. Garnish with extra radish slices and/or sprigs of fresh dill if desired.