Longan agar jelly (Vietnamese: rau câu nhãn) is an easy Vietnamese dessert. You only need to pour hot agar liquid into longan flesh and cool it down. However, the tri-color version is much more difficult and requires extra time. The base color is white, but you need strawberry syrup and mint syrup to add 2 extra colors.
First, you need to remove the seeds from fresh longans, but do not cut the flesh. The final outcome is cup-like longan flesh. Second, you will stuff the longans with colorful jelly (which is mixed with fruit syrups), and wait them to get cooled. Third, in jelly molds, you place the agar-stuffed longans into each mold, and finally pour the agar paste into molds.
The longans in this dish must be the fresh ones with thick flesh and small seeds. Also, jelly molds are needed.
Put 200 g (7 oz) of rock sugar and 2/3 of your jelly powder in the bowl, mix well. In a pot of fresh coconut water, add the mixture, stir well over medium heat so that all ingredients are dissolved and they do not get clumped. After the clear agar solution comes to a boil (after about 5 mins), reduce the heat to keep it warm. In two separate bowls, add strawberry and mint syrups respectively. Add 100 ml clear agar jelly you just made to each bowl, and mix well. Please note that the remainder of clear agar jelly will be used later.
Pour 400ml of filtered water into a pot over medium heat, add the rest rock sugar and agar jelly, stir well to dissolve the ingredients. Then add 60 ml or about 80g of condensed milk, and stir well. Next, add the longan puree and stir well until the mixture come to a boil again, the reduce the heat to low to keep it warm.