Găng jelly (Vietnamese: thạch găng) is a type of green jelly made from the leaves of Catunaregam tomentosa plant, which is a shrub tree with small thorns, commonly grown as hedges. Catunaregam tomentosa is known as găng trắng in Vietnamese, and has several botanical synonyms: Gardenia dasycarpa, Gardenia tomentosa, Randia dasycarpa, Randia tomentosa, and Xeromphis tomentosa.
Găng jelly is similar to Sương sâm jelly, which is made from the leaves of either Tiliacora triandra or Tiliacora acuminata plants. Like other green jellies, găng jelly can be made from crumpled green leaves (traditionally), dried leaves or dried leaf powder (commercially).
Discard any thorns. If you're using dried leaves, soak in water for a few minutes. Rinse and drain.
Pour half of the water into a pot. Put the leaves into a cloth bag and squeeze forcefully or crumple it for 7-10 mins. Pout the rest water into the pot the squeeze the bag again. Stop until you have a dark green liquid. Strain through a sieve to remove any impurities or lumps.
Add 150 ml clear lime water into the leaf liquid pot. Stir until the liquid is fully mixed. Keep the pot in dry places for about one hour.
In a saucepan, melt sugar and add 200ml water and continue to cook until the sugar is dissolved. Add some ginger slices, jasmine flowers or pomelo flowers for aroma.
In a serving bowl, scoop the leaf jelly fro the pot into the bowl, and pour the caramelized sugar water. This jelly may not be sliced into cubes like other type of jelly. Add some ice cubes.
Clear lime water makes the jelly more crunchy.
If you're using leaf powder, adjust the water, or just follow the producer instructions.
Drop 2-3 drops of banana essence when serving, if any.