I'm thinking some Chanterelles, sauteed in butter before adding to the sauce. Pour both the mushrooms, and butter into the sauce.
Another addition that might work could be a sprinkling of any of the Italian hard cheeses, such as Asiago, Pecorino-Romano, and of course, Parmesano-Regiano.
If you want to go in a different direction, you might add brown sugar, worcestershire sauce, and a bit of liquid smoke to turn it into a chicken with bbq sauce kind of dish.
Of course this would be for the next time you made it.
Seeeeeya; Chief Longwind of the North