Chop up the orange flesh and place in a saucepan with the 90g caster sugar and 75ml water.

Stir over a gentle heat until the sugar dissolves then bring to a simmer and cook for 20 mins.

Put the sheet of gelatine in a jug of cold water to soften for 10 mins.

Blitz the cooked orange mixture with a hand blender until fairly smooth, then to enrich the jelly appearance, add a couple of drops of red and yellow food colour.

Finally add the Cointreau and the gelatine.

Leave to cool and firm up.