- 6 blood oranges
- 2 egg yolks
- 1/2 teaspoon lemon juice, or to taste
- 2 1/2 tablespoons sugar
- 1 1/2 tablespoons Grand Marnier or other orange-flavored liqueur
- Garnish: 3 tablespoons coarsely chopped pistachios
- Finely grate enough zest from 1 orange to measure 1/2 teaspoon. With a sharp knife cut peel from oranges, including all white pith, and cut sections free from membranes. Squeeze enough juice from membranes to measure 2 tablespoons. Divide sections among 4 stemmed glasses.
- Have ready an instant-read thermometer in a measuring cup of hot water. In a metal bowl whisk together zest, yolks, orange and lemon juices, sugar, and liqueur until combined well. Set bowl over a saucepan of simmering water and cook mixture, whisking constantly, until tripled in volume and thermometer registers 140°F., 3 to 5 minutes. Cook sabayon, whisking, 3 minutes more, or until thickened enough so that strokes leave a clear path.
- Spoon sabayon over orange sections and garnish with pistachios.