Stir together orange juice, eggs, and sugar in a small saucepan. Place over low heat, and stir constantly until the sugar has dissolved, and the mixture is very thick. Once thick, strain mixture into a large bowl, and stir in butter cubes until melted. Cover and refrigerate until cold, about 2 hours.

Fold whipped cream into cold egg mixture until smooth. Recover and refrigerate for 3 hours.

To assemble, place half of the cubed angel food cake into the bottom of a trifle bowl. Spoon on half of the whipped cream mixture, and sprinkle with half of the Mandarin oranges. Create a second layer with the remaining angel food cake, whipped cream mixture, and Mandarin oranges. Refrigerate until ready to serve.