Tomatoes cut in half and squeeze them like lemons, blanched for 1 minute in boiling water and leave to drain on paper. Peel and cut into small cubes. In this kind must be 800 Lemon juice and sugar to boil up until sugar is melted. Tomatoes are added to lemon juice. Once it boils, remove from heat. Allow to cool and collect it in the refrigerator overnight. The next day, add the vanilla and put to boil until it thickens, to remove the foam. Once thickened enough, add balsamic vinegar while stirring. If a drop of jam on the plate does not flow means it is ready. Packed in jars, pay with caps down for about half an hour.