Bring 0.5 l of water to the boil and boil the black tea in it for 3 minutes. Remove the tea bags.
Pour in the juice of one lemon. Add the frozen fruits. Let it steep for 15 minutes. Crush the fruits with a mortar or similar so that all of the juice comes out.
Put everything through a sieve and add the syrup, this can vary depending on the taste and strength of the syrup, just try it in between.