Weight the dried platostoma palustre plant 40 g which is around 3 cups.
Wash, soak and rinse the dried platostoma palustre plant to remove dust and sand.
In a big pot, add 8 cups of water, ½ teaspoon baking soda and the washed platostoma palustre plant. Then, turn on a high fire and boil it. When it's boiling, turn the fire to medium small and simmer for 30-45 minutes.
After that, let it cool off, use your hands to rub the plants to get the slimy thing out and mix with the liquid.
Then, use a strainer bag to remove the big pieces of herb. After that, use a fine strainer to remove smaller pieces of herb. Remember to do this step twice. (The result of liquid is around 4-4.5 cups. And, I like 4.5 cups texture better.) Next, in a small container mix 4 tablespoons of water and 4.5 tablespoons of cornstarch or potato starch.
Pour the cornstarch mixture from step 7 into the liquid, keep stirring until it thickens. (Also, potato starch has better texture. However, cornstarch works well.)
Pour the thicken mixture into a container and refrigerate for 3-6 hours.
After that, cut the grass jelly into cubes.
You can serve with syrup.
Or, serve it with condensed milk, milk, coconut milk and fruits.