Mix almond flour and coconut flour in a bowl.
Add erythritol, salt, and baking powder and mix evenly.
Add egg and melted unsalted butter, then knead into dough.
Shape into small round pieces.
Bake in an air fryer or oven at 170°C (338°F) for 12 to 15 minutes.
Coat the baked yakgwa in a syrup made with olive oil and erythritol.
Place on a paper towel to cool.