1. Combine sugar, cornstarch and salt in top of a double boiler; stir in orange juice. Cook over simmering water, stirring constantly, until mixture is thickened and bubbly.
2. Gradually stir one-fourth of hot mixture into yolks; add to remaining hot mixture, stirring constantly, 2 minutes or until mixture thickens. Remove from heat; stir in Triple Sec.
3. Chill thoroughly. Just before serving, stir in orange sections. Serve over angel food cake.