1.Place milk, cream, sugar and zest in a medium saucepan. Cook, stirring, over low heat, until sugar dissolves and mixture comes almost to the boil; remove from heat.
2.Sprinkle gelatine over the water in a small heatproof jug; stand jug in a small saucepan of simmering water. Stir until gelatine dissolves; cool 5 minutes. Stir gelatine into cream mixture until combined. Divide panna cotta mixture into 3 heatproof jugs.
3.Bring blood orange juice to the boil in a small saucepan; reduce heat to medium, and simmer for 5 minutes or until liquid is reduced to about 2 tablespoons. Cool for 5 minutes, then add to one jug of the panna cotta mixture.
4.Repeat step 3 to reduce the orange juice to about 2 tablespoons. Cool for 5 minutes, then add to the second jug of the panna cotta mixture; tint a pale orange with a couple of drops of food colouring.
5.Stir orange blossom water into the last jug of panna cotta mixture.
6.Rinse 24 x ⅓-cup (80ml) dariole or plastic moulds with cold water – do not dry; place moulds on a tray. Pour each panna cotta mixture into 8 moulds. (You’ll have 8 blood orange, 8 orange blossom and 8 orange panna cottas.) Refrigerate panna cottas for 6 hours or overnight.
7.Carefully turn panna cotta out onto a platter (see tip, right). Top blood orange panna cotta with blood orange segments, orange panna cotta with orange segments and the orange blossom panna cotta with edible flowers.
To unmould panna cotta, rub the outside of the mould with a hot kitchen cloth. Holding a mould upside down in your cupped hand, shake gently until the panna cotta releases from the mould; carefully transfer to a serving platter.Note