its a vietnamese dessert called banh dau xanh, very nice with tea, this is so simple that u could see variant of it originate from all over the world.
Ingredients ( for 4 person or 1 person at 11pm):

• mung bean: 500gr
  sugar: 200gr
  salt: little bit or just dont use it

step 1: Prepare the Mung Beans: Wash and rinse the mung beans several times to remove all dirt. Soak the mung beans in water for about 5 hours.
step 2: Cook the Mung Beans:
On the stovetop: Place the mung beans in a pot and add water just covering them. Add a pinch of salt. Bring to a boil over medium heat, then reduce the heat to low, cover with a lid, and simmer until the mung beans are soft and easily mashed with fingers or a spoon.
In a rice cooker: Place the mung beans in the rice cooker pot with a pinch of salt and add water just covering them. Cook the mung beans as you would cook rice in the rice cooker.
step 3: blend the Mung Beans:
just blend until it look powdery, even if u blend too much it probably wont get past the powdery ish stage
step 4: cook them again:
boil it, pour sugar in, stir it until it only a bit moist, enough so that u could shape it like a powder cake. Dont stop stiring, there sugar in there
step 5: shape the cake:
now looking at those dry mud u made, it should be pretty, let it cool down, make it into any shape u want (but like make it so it smaller than a 3cm cookies, u gonna bake it later, but smaller is ok cuz u bake it till it dry as sahara)
step 6: BAKE the cake:
IN THE PAN -> INTO THE OVEN -> 45°c TO 45°c FROM 1 TO 2 HOURS
step 7: EAT the cake

good with tea, water, liquid of unamed but not too sweet or not sweet at all cuz this is sweet