Let's cut the ingredients for Hamburg Steak. Cut the onion in half. Slice into the onion with the root end attached. Make cuts across the onion parallel to the cutting surface. Chop across the other two cuts and mince well.
Chop off the broccoli stalk and cut the flower heads into smaller pieces. Peel the stalk and chop into bite-size pieces.
Cut the steamed potato into 4 pieces. Cut the tomato in half and slice it into half moons. Grate the garlic clove.
Let's fry the chopped onion. Heat olive oil in a frying pan. Stir-fry the onion for 2 to 3 minutes at high heat.
Stir 5 to 6 minutes until colored at medium heat. Remove, and let the onion cool on a plate.
Let's cook the vegetable side dish. Heat olive oil in a pan. Saute the broccoli and potato at high heat until browned. Add salt and pepper.
Sprinkle on some water, put a lid on and cook the vegetables for 2 to 3minutes.
Remove the lid, and stir the vegetables. Toss the pan to cook evenly and place the vegetables on a plate. Serve the tomato, broccoli and potato on a plate.
Let's make the meat mixture for hamburg steak. Add milk to the breadcrumb. Stir, and moisten the breadcrumbs.
Season the meat mixture with salt, pepper and nutmeg. Knead the meat mixture in a bowl until a bit gooey.
Add 2/3 of the caramelized onion and breadcrumbs to the mixture. Crack the egg into a bowl and add to the mixture.
Knead the mixture thoroughly. Clean your fingers and and divide the mixture in half.
Pour some oil onto clean hands. Shape the meat mixture into a ball. Toss from one hand to the other and remove the air inside. Removing the air from the meat mixture will prevent it from breaking into pieces while being cooked.
Shape it into an oval and flatten its center part. Place it on a baking tray. Repeat the process to shape another meat ball. If the meat mixture is too soft to shape, let it cool down in a fridge.
Let's fry the hamburg steak. Heat olive oil in a pan. Lightly press on the meat and make a dent in the center. This will reduce the cooking time.
Rotate the meat with a spatula to cook evenly. Cook them until they are golden brown on the bottom. Flip them over and brown the other sides evenly. If there is too much oil in the pan, remove with paper towel.
Add measured water (approx. 100ml/3.4 fl oz) and cover. Steam and fry until the water has evaporated almost completely.
Remove the lid. Pierce the meat to check that its juice is clear. Turn off the burner and serve the hamburg steak on a plate.
Let's make onion sauce. Add water, soy sauce and mirin to the pan. Put the remaining caramelized onion in the pan and cook at medium heat.
When it starts to boil, add butter and grated garlic. Stir lightly. When the butter is dissolved, turn off the burner.
Pour the onion sauce onto the hamburg steak. The onion sauce flavored with soy sauce and butter goes great with steamed rice.
If you prefer lighter taste, ponzu sauce is also a great match, adding a little zest to the dish. Garnish with a shiso leaf and grated daikon radish to taste.
This recipe is very popular along with various kinds of sauces such as demi-glace, mushroom and grated daikon ponzu sauce.