Blitz the tomatoes in a blender. Add the gelatine, mix well and freeze for at least 8 hours
Remove the tomato block from the freezer and wrap in a muslin cloth. Place in the fridge to defrost over a container to catch the tomato water. Keep it very cold so it remains a thick liquid
Place the fennel in a medium-sized saucepan and cover with water. Simmer over a medium heat until cooked
Once cooked, season with salt and blend in a food processor
Place the cream and 350g of the fennel purée in a 500ml espuma gun. Charge with two N2O charges and place in the freezer
To serve, prepare cold glasses and pour the tomato water in the bottom. Pipe the fennel foam on top and serve immediately
