This dessert place is inside the extremely popular Konjiki Ramen. They have their own small seating area if you want to dine in. I went around 6pm on a weeknight and didn't have to wait to order. I got the houjicha soft serve and thought it was just average...it tasted more like a mix of chocolate ice cream and houjicha than just houjicha. It also looked grainier (less smooth) than other houjicha soft serves I've tried.
Update: Upgrading rating from 3 to 4 stars. Tried their houjicha latte and it was quite good. No weird chocolate flavour (maybe that was an off day?). Strong houjicha taste and very smooth. Will come back to try their matcha soft serve one day.