Preheat the oven to 180°C.
In a bowl, mix almond flour, baking powder, salt, and matcha powder.
In a separate bowl, combine egg, coconut oil, erythritol, yogurt, and citron preserve (yujacheong).
Add the wet mixture into the dry ingredients and knead into a dough.
Shape the dough into a round or triangle.
Place on a baking sheet and bake for 20 minutes.
After cooling, lightly brush citron preserve (yujacheong) on top.