Wash, clean and drain the strawberries. Weigh 1.4 kg of flesh and cut into small pieces. Mix strawberries, lemon juice, aperol and jam sugar in a large pot.
Bring to the boil over high heat while stirring. Boil for at least 4 minutes while stirring continuously. Skim off any foam that may have formed.
Immediately pour the jam into clean twist-off jars, close the jars and place them on the lid for about 5 minutes. Turn them over again and let them cool down. Store jam in a dark and cool place.