Sweet longan jelly with delicate fruit flavor and soft texture is a refreshing dessert. A family recipe with fresh, tropical longan sweetness.
Drain the canned longan, reserving both the fruits and 1/2 cup of syrup for later; set aside.
In a medium saucepan, combine agar-agar powder and water. Whisk to dissolve completely, then let stand for 5 minutes to hydrate.
Bring the mixture to a gentle boil over medium heat, stirring constantly. Once simmering, add sugar and reserved syrup. Continue stirring until sugar and agar-agar fully dissolve, about 2 minutes.
Remove from heat. Stir in lime juice and half of the longan fruit pieces. Immediately pour mixture into a shallow serving dish or individual molds.
Allow the jelly to cool at room temperature for 20–30 minutes, then transfer to refrigerator for at least 1 hour. When set, top with remaining longan fruit before serving.