Pour ½ cup of juice in a small bowl. Sprinkle gelatin over the juice and let stand until gelatin is moistened.
In a small saucepan, bring 1 ½ cups of pomegranate juice just to boil over medium heat.
Whisk in the dissolved gelatin and simmer until gelatin is completely dissolved.
Remove from heat and let cool slightly. Pour desired amount over custard. Refrigerate until set.