Put oatmeal and flour in a bowl and mix well.
Cut cold butter into small pieces, add to the bowl, and mix with your hands until it becomes crumbly.
Add sugar, baking powder, salt, and milk, then complete the dough.
Roll out the dough to 2cm thickness and cut into the desired shape.
Bake in a preheated oven at 180℃ for 20 minutes.