Shake the dandelion flowers to let small insects fall out. Then pluck the fine yellow petals off. It is recommended to wear gloves for this work - otherwise the fingers will be very yellow.
Peel the lemon finely and cook to a syrup with water and sugar. Add the petals and let everything simmer gently for about 10 minutes.
Let the syrup stand in a cool place for 24 hours. Then strain.
Squeeze the lemon and add the juice to the syrup, bring to the boil again briefly and pour it into bottles with twist-off caps while still hot. Close immediately and let cool upside down.
The syrup is delicious in sparkling wine or mineral water.