To prepare Banh It Tran/Vietnamese Mung Bean Dumpling, begin by washing and soaking mung beans for 30 minutes. Pressure cook or boil on the stovetop until it becomes soft.
Then, heat a pan with oil and sauté the onions until softened; drain using a slotted spoon and add to the soft mung beans. Now, add pepper and salt to taste.
Next to that, sauté the green part of the onions in the same oil for 3-4 minutes before removing from the heat to cool.
For dough preparation, mix together flour, salt, and water (1 tablespoon at a time) until a soft dough forms. Allow the dough to rest for 10 minutes while covered. Then, divide into 5-6 portions and roll each piece out flat. Place a ball of mung beans filling onto the flattened dough before bringing it together to form a ball.
Bring 1.5-2 cups of water to a rolling boil in a pan, then add 2 or 3 dumplings at once (make sure they don’t touch each other). Stir on and off for 8-10 minutes, until the dumplings float on top. Then, remove them using a slotted spoon and place them into cold tap water for 5 minutes. Now, put the cooked dumplings on a serving plate/bowl and drizzle with onion oil before serving with Nuoc Cham Chay.