Recipe: Sweet Potato Zenzai (紫芋ぜんざい)

As far as I know, ‘Zenzai’ usually describes a sweet red bean soup with small mochi in it. I had it a few times before, but never liked it because it was just too sweet for me. So I had kinda decided that Zenzai was simply not for me. That was until I stumbled over a cute little café in Nikko that was advertising Murasakiimo (Japanese purple sweet potato) Zenzai. Of course I had to go in and try it! I instantly loved the combination of warm soup and cold ice cream with the mochi adding another dimension of texture to the dish.

I don’t know if Murasakiimo Zenzai is actually a thing and I just don’t know about it or if this was a somewhat special dish, but I liked it so much that I decided to recreate it at home. Since I couldn’t find a recipe online, I just made my own version of this wonderful fall dessert and thought it might be interesting to share, in case there are more sweet potato lovers out there who don’t like the traditional sweet red bean soup and are looking for alternatives.

My version is not very sweet, because I didn't want to overpower the sweet potato flavor. Instead, the ice cream adds sweetness and creaminess to the whole dish. The mochi make it more fun to eat and were also slightly sweet in my case.

So here is my Murasakiimo Zenzai recipe, inspired by a small café in Nikko:

Ingredients for about 3-4 servings

1 large (=320g) purple sweet potato (紫芋 – むらさきいも)
1 tablespoon brown sugar
small pinch of salt

Toppings

Small mochi (I used frozen)
Vanilla ice cream

Instructions

    1. Cut the sweet potato into small cubes (you can peel it if you like, but I don’t think it’s necessary) and place it together with the sugar and salt into a sauce pan.

       
    2. Add water to the point where the sweet potato is not quite covered and simmer with a lid until the sweet potato becomes tender.
       
    3. Mash with a potato masher or fork until it reaches your desired consistency. I left mine a little chunky.
       
    4. Taste your zenzai to adjust for sugar if you like it sweeter and transfer to your serving dish while it’s still hot. Top with ice cream and mochi and enjoy!

Notes

    • The recipe probably also works well with the normal satsumaimo (さつま芋), since satsumaimo and murasakiimo taste fairly similar, but I haven’t tried it.
    • I used unrefined dark sugar (黒糖), which added another nice flavor dimension to the dish.
    • You can use any ice cream flavor you like, something like plain milk or rum raisin would also be a good match. Mine was homemade cinnamon rum ice cream, which was an awesome combination.

This is the little café in Nikko where I ate Murasakiimo Zenzai:
お茶処 三天甘太郎
〒321-1405 栃木県日光市石屋町420-1

The shop owner is a lovely old man who is very happy to chat with customers and give recommendations about where to go in the Nikko area (only in Japanese though).