(Adapted from http://bebeloveokazu.wordpress.com/2010/05/04/tsubuan-red-bean%C2%A0paste/#more-1390)

Less Sweet Tsubuan (Red Bean Paste)

2 cups azuki beans (red beans)
3/4 cups granulated sugar
1/2 teaspoon salt
4-6 cups water
In a large bowl, soak azuki beans in water overnight.

The beans will expand over night, and some may even split. Rinse the beans, transfer to a large pot, add water, bring to a boil.

Turn down the heat to medium and simmer beans for about 10 minutes. Skim foam and any residue that floats to the top of the pot.

Turn down the heat to low and simmer the azuki beans for about 1 1/2 hours, or until softened. Stir beans occasionally to make sure that the beans don’t stick to the bottom of the pan and burn.

A tiny glitch:

I had to add an extra 1 1/2 – 2 1/2 cups of water because not all of the beans were tender and I had to cook this for an additional, what seemed like, an hour. Also, it looked like there were still several beans that hadn’t split open and fallen apart so I called my mom and asked her if it was OK to have some whole beans left. She said in Japanese, “DAME-YO!” This is what I tell my bebe E when she spits out (more like motorboats-out) her food that she doesn’t want to eat. It means, “NO” or in my case, “NO, BAD BEBE!” My mom told me to add more water and cook it longer. So I did.

Most of the liquid should boil off. If the azuki beans have a slightly watery texture. Don’t worry. As the koshi-an filling cools, this water will be absorbed into the beans, and you will end up with a thick, creamy filling.

Add sugar and salt into the tsubuan mixture and stir constantly for about 5 minutes until the sugar dissolves. Don’t leave the stove unattended because your koshi-an will burn! Remove from heat and let cool to room temperature.

Tsubuan can be covered and stored in the fridge for 3-5 days. I’ve stored some in the freezer before and defrosted it in the fridge. It didn’t taste as fresh as when it was first made, but it was still good. Stay tuned for wagashi!