I mixed green tea into the batter and added the kuromame (black beans) and kuri (chestnut).
Like the kinkan (kumquats), the kuromame and kuri were also packed in syrup.
Use this recipe, but disregard the earl grey tea and nibs. Also, instead of 150 grams of flour, use 140 grams of flour and 10 grams of powdered green tea.
Bake at 350F (180C) for 25 minutes. Test for doneness with a toothpick.
NOTES: I had a bit of a disaster in the kitchen. While defrosting my butter in the micro, it sort of "blew-up", leaving me with a lesser amount of butter. I added some EVOO to make up for it, not sure if this is what made the muffins drier. Still, the green tea flavor really came through in these muffins. Cutting the sugar was a good call too, the beans and chestnut were sweet.