For the panna cotta

1. Place blood orange juice in a small bowl and sprinkle gelatin over the surface.  Allow to sit for 15 minutes to soften.
2. Meanwhile, in a medium saucepan, heat cream, sugar and zest over medium heat and bring just to a boil until sugar dissolves.  Remove from heat and whisk in the gelatin until dissolved and mixture is smooth.  If gelatin is not fully dissolved then return saucepan to the stove and whisk mixture over low heat just until dissolved (do not bring to a boil).
3. Pour mixture into ramekins or glasses, leaving room for a thin layer of syrup, and refrigerate for at least 4 hours or up to 3 days.

For the gelée

1. When the panna cotta is fully chilled, in a medium bowl whisk the hot water and gelatin until dissolved.  Add the sugar and continue to whisk until dissolved.  Whisk in the blood orange juice until mixture is well combined.
2. Allow to cool for 10 minutes and then pour over the chilled panna cotta.  Chill in the refrigerator for at least 1 hour before serving.
3. Remove from the refrigerator 15 minutes before serving.