Cut potatoes into 8 pieces and soak in water. Drain. Cut carrot into bite-sized pieces. Slice onion into 1cm wedges. Trim green beans and cut into thirds.

Heat salad oil in a pan over medium heat. Add ground meat and cook until color changes. Add potatoes, carrots, and onions, stirring until coated with oil.

Add seasoning ingredients (sake, mirin, sugar, water) and bring to a boil. Cover and simmer on low heat for 8 minutes.