Carefully select the fruit, wash and drain well. Do not crush blueberries. Covered with jam sugar and leave to soak for 24 hours. Put them into a saucepan and boil them for 4 minutes until they are bubbling.
Shortly before the end of the cooking time mix in almond slivers. Stir in gin and lemon juice, pour hot into clean glasses and close. Results in about 4 glasses of 450 grams each.