Mince the onion and microwave it in a heatproof container at 600W for 1 minute. Trim the root of the shimeji mushrooms and separate them by hand. Slice the garlic thinly.

Mix the rice with butter and parsley in a bowl.

In another bowl, combine the ground meat, minced onion, salt, pepper, nutmeg, breadcrumbs, and milk. Mix until sticky, then divide into 8 portions and shape into balls.

Heat olive oil in a frying pan over medium heat. Add the meatballs and cook while rolling them to brown the surface. Add the shimeji mushrooms and garlic, sauté for 1 minute, then pour in the white wine. Bring to a boil, cover, and simmer on low heat for 10 minutes.

Add the heavy cream, salt, pepper, and consomme to the pan. Simmer for another 5 minutes.