Wash the dandelion blossoms, put them in a saucepan with the lemon wedge and just cover them with water. Bring to the boil over the highest heat, then simmer for 8-10 minutes.
Pour off the flowers through a sieve over a measuring beaker - they can now be disposed of.
Fill up the liquid in the measuring cup with water to 400 ml and pour it into the pot. Stir in the preserving sugar and the very small chopped mango pieces.
Bring to the boil once, then simmer for 5 minutes, stirring frequently.
After the cooking time, pour into glasses immediately (twist off) and close.