Ensure the cherry tomatoes are washed but that no water is left on the surface. Lay out everything in advance since you'll need to work quickly once the hot caramel is ready:Prepare a baking tray covered in baking paper, 12 cocktail sticks (or brochette/cake pop sticks), a plate coated in the seeds, plus a bowl or tin (waterbath) filled with hot water that can hold the saucepan of caramel (this is so that the caramel doesn't harden too quickly while you work). Pierce each cherry tomato with a cocktail stick.
In a saucepan, place the sugar and water together and stir until the sugar is dissolved.
Put on a medium heat and, without stirring, leave for about 6 minutes until the caramel starts to form. The sugar will bubble furiously and the caramel will start to brown slightly - keep your eye on it for the next couple of minutes. Add the fleur de sel salt to the caramel or roll in the salt with the seeds.
Take the caramel off the heat as soon as the colour is light brown and place the saucepan in the warm water bath and work quickly. Dip each cherry tomato into the caramel then immediately roll in the seeds and the salt.
Place on the baking tray to set for a minute.
Serve pierced in a giant tomato or half a grapefruit covered in aluminium foil, for example.It's best to serve them as close as possible to preparation. I recommend keeping them out at room temperature, as placing them in the fridge could result in the toffee melting.