Miya 23 suggested soaking beans in hot water overnight, then using fresh water and cooking them until very tender. They will firm up when adding sugar; and you need to add at least the same weight of sugar as beans.
Then add 切り餅, which you can broil under the grill
Serve this with something salty, like 大徳寺なっと or salted sea weed
Instead of using a pair of chopsticks, use one くろもじ and a helper, 利休-shaped helper chopstick; because conceptionally, it's a sweet and not 懐石.
けいこ (XI 23) said that あわぜんさい is more common, which is cooked milled mixed with little 餅 pieces and with a drop of liquefied あん. I didn't think it looked particularly great; and while she argues it's more traditional for CNY, I think I prefer the soup.