Lightly grease the insides of a 1 l jelly mould with a little neutral oil – you can skip this step if you're serving the jelly straight from a dish or bowl.
Strain the grapefruit and orange juices into a saucepan, to extract any pulp.
Bash the bay leaves a bit to release some of their oils, then add them to the juice pan with the sugar.
Bring the mix to a simmer, then, once the sugar has dissolved, take off the heat, cover and leave to infuse for at least 30 minutes, and ideally two hours.
Put the gelatine leaves in a small bowl of cold water, leave to soften for five minutes, then lift out and squeeze out the excess water.
Remove and discard the bay leaves from the juice pan, then reheat the juice until it's warm to the touch.
Add the gelatine, stirring until it's completely dissolved, then pour into the oiled mould.
Leave to cool to room temperature, then chill in the fridge for four to six hours, until set.
To release the jelly, dip the base and sides of the mould briefly in warm water, then flip it upside down on to a serving plate and lift off the mould.
Lightly whip the cream to very soft peaks and serve alongside the jelly.
