Combine breadcrumbs and milk in a bowl and let soak.

Remove strings from celery and slice diagonally. Cut celery leaves into bite-sized pieces.

Mince onion and microwave in a heatproof container for 1 minute at 600W. Let cool.

Add ground meat, onion, and seasonings to the breadcrumb mixture. Mix until sticky and divide into 8 portions. Shape into balls.

Heat salad oil in a frying pan and cook meatballs until browned. Cover and steam for 5 minutes.

Add sake, water, and consomme to the pan. Bring to a boil, then add celery and cover. Cook for 3 minutes.