Blanch the chard leaves. Finely chop the chard stalks and the onion and let them turn translucent in heated butter or oil. Add the pressed garlic, the chopped herbs and the chopped mushrooms and fry briefly. Stir in the beaten eggs and mix with the chard leaves.
Grease a baking dish, sprinkle with breadcrumbs and pour the chard mixture into the dish. Sprinkle with cheese and bake at 180 ° C for about 20 minutes.