Soak the gelatin sheets in cold water.
Wash the tomatoes, remove the stems, place them in warm water and remove the skin (émonder).
Roughly chop the tomatoes.
Stew the finely chopped onion in the olive oil.
Add the lemon thyme and half of the tomatoes and leave to soften.
Season with pepper and salt.
Add the cinnamon and soaked gelatin sheets.
Remove from the heat and add the rest of the tomatoes and finely chopped basil.
Season to taste, if necessary.
Store in the refrigerator.