The omelet itself is made of ghee, so it has what you call "oily taste". The additive you mentioned should be "yolk essence". In addition to increasing costs, the smell of eggs is also a big problem. Therefore, additives such as "egg yolk powder" are usually added to egg rolls, which will enhance the flavor besides adding Huang Zhi. It will be much healthier to make your own suggestions and buy better "ghee" to make dough.