Put some ripe blackberries in hermetically-sealed preserving jars. Once the jars have been filled, top with a bit of freshly-squeeze lemon juice and cover with simple syrup made with 1 litre of hot water and 300 gr. Of sugar.
These jars are then pasteurized in boiling water for approximately 20 minutes and are stored in a cool dry place once cold.
You can use the preserves afterwards to make blackberry tarts by beating whole eggs in bowl, adding the blackberry preserves, a dash of the preserving liquid and a pinch of salt.
Bake in the oven by laying out the dough in a fine layer on a baking sheet.
We call this recipe “blackberry blood” because the preserves take on the rich deep scarlet colour of blood.