Using a vegetable peeler, remove a strip of zest from one of the oranges and chop enough to measure 1/4 tsp. Using a knife, peel skin and pith from oranges and cut in between the membranes to remove the sections. Using hands, lightly crush the basil sprigs and toss in a large bowl with the orange sections. Cover and chill 2-6 hours. Mince the 1/2 cup basil. In a medium bowl combine the egg yolks, sugar, wine and reserved orange zest. Place over a saucepan of simmering water and whisk until the zabaglione is frothy, thick, and doubled in volume, about 5 minutes. Stir in the minced basil. Drain the orange sections and remove basil sprigs. Divide among 3 dessert dishes and spoon a heaping tablespoon of zabaglione over each one.