Fry the onion cubes and the thinly sliced mushrooms in hot butter until everything has turned some color.
Briefly toast the rice in the hot oil and add the broth. Cover and cook over low heat for about 15 minutes.
Mix in half of the grated cheese and mix with the mushroom mixture.
Place in a greased casserole dish (approx. 3-4 cm high) and make round dents with the ladle. Let a cracked egg slide into each dent. Just sprinkle the rest of the cheese on the rice so that the rice doesn`t dry out in the oven. Bake at approx. 180 ° C (top and bottom heat) until the eggs have the desired firmness.
Sprinkle with chopped parsley and apply in the form.