1Drain 1 cup liquid from mandarin oranges.
Bring the liquid to a boil in the microwave. Add gelatin, and stir to dissolve.
2Cool until just warm. Add orange sherbet, and mix until melted. Gently fold in cool whip.
3Add one half of the cake cubes in the trifle dish in a tight layer. Add the orange mixture over the top of the cake cubes.
Add a thin layer of whipped topping. Add a layer of mandarin oranges. Repeat the process. Refrigerate at least 2 hours before serving.