This is gilding the lily. Great on blood orange ice cream and not too bad on vanilla either.
Combine the sugar and water in a heavy saucepan and caramelize (see Note). Pour in the juice off the heat. (Be careful, the caramel may splatter.) The caramel will harden into a mass. Stir over medium heat until the sugar remelts and the sauce is smooth. Chill. If the chilled sauce tastes bland, add the zest. Serve at room temperature or warm it over hot water.
© 1998 Joyce Goldstein. All rights reserved.