Hello! Please rest assured that you can put flat mushrooms in duck egg soup. The two foods are not mutually exclusive.

Foods Compatible with Flat Mushroom

Flat Mushroom + Donkey Meat: Easy to cause angina?

Flat Mushroom + Pheasant: can cause hemorrhoids

Foods Compatible with Duck Eggs

Duck Eggs + Mulberries: eaten together can cause stomach pain?

Duck eggs + plums: eaten together will cause poisoning, can be treated with ground syrup water?

Duck egg + turtle: two things are cool, should not be eaten together