Step：

1. Place butter at room temperature until soft, then cut into small cubes;
2. Preheat oven to 200℃;
3. Add eggs to a bowl and beat eggs well;
4. Add sugar and stir it well then sift in self-rising flour, baking powder, parmesan cheese powder and mix them thoroughly. Stir in butter and Korean citron tea until just smooth for later use;
5. Place baking sheet on muffin cases and fill them half full;
6. Put them into oven and bake for 20-25 minutes then leave them until cool for serving.