Rinse the berries, trim, cut the strawberries into small pieces and pick the currants from the stem. Mix the berries with the same amount of jam sugar and lemon juice and let stand for 1 hour.
Then bring to a boil in a pot and cook for 4 minutes until bubbly. Pour into glass jars, seal and turn upside down for 10 minutes. Turn again and let cool completely. Store in a cool and dark area.