Peel and cut the potatoes, carrots, and onions into bite-sized pieces.
Cut the beef into bite-sized pieces.
Heat cooking oil in a pot and sauté the beef.
Once the beef is cooked, add the potatoes, carrots, and onions and stir-fry together.
Add 200ml of water and bring to a boil.
When it boils, skim off the foam and add sugar, soy sauce, mirin, and tsuyu.
Simmer over medium-low heat until the potatoes are tender.
Serve the finished Nikujaga in a bowl.