Rinse the adzuki beans under cold water.

Soak the rinsed beans in a bowl of water for at least 4 hours or overnight.

Drain the soaked beans and transfer them to a medium pot. Add 3 cups of fresh water, then bring to a boil over medium heat.

Once boiling, reduce the heat to low and cover the pot. Let the beans simmer for about 45 minutes to 1 hour, or until they are tender.

Once cooked, drain the beans using a colander.

Using a potato masher or food processor, mash or blend the beans until smooth.

Add sugar and salt to the mashed beans, then mix well.

If you prefer a smoother texture, stir in the vegetable oil.