Finely grate the zest from the oranges and squeeze the juice. There should be about 3 tablespoons zest and 2/3 cup juice.
In a medium saucepan, combine the water and the sugar. Cook over medium heat, stirring, until the sugar dissolves, about 3 minutes. Remove from the heat.
In a large bowl, whisk the egg yolks until very light. Slowly add the hot sugar syrup in a thin stream, whisking constantly. Pour into a large saucepan and cook over low heat, stirring with a wooden spoon until slightly thickened.
Strain the mixture into a medium bowl, and set it in a larger bowl partialy filled with ice water. Stir in the orange juice and zest. Let cool, stirring occasionally. (Or chill overnight in refrigerator.)
In a large chilled bowl, using an electric mixer with chilled beaters, whip the cream until stiff peaks form. Fold the cream into the cooled orange custard mixture. Freeze in an ice cream freezer according to manufacturer's instructions. Transfer to a covered container and place in freezer until serving time. If the gelato becomes too firm, place it in the refrigerator for 30 minutes before serving.
Recipe courtesy of Michele Scicolone, La Dolce Vita, William Morrow 1993 hardcover, The Ecco Press 1999 softcover