Hamburg steak (ハンバーグ) is probably the most popular item on a Japanese kids menu, but I never liked it growing up. It's very similar to a salisbury steak and a predecessor to the hamburger. Once the patty was squeezed between two buns, the hamburg steak was quickly forgotten in the US. But the bun-less patty remains widely popular still in Japan.
I never liked the dish because whenever I had it, it was always dry and tasteless. Today, I'll be sharing with you how to make a juicy and delicious hamburg steak, one you will want to make over and over again. There are a couple tricks that make this one particularly delicious. The first trick is not buying the leanest ground beef. I've mentioned this before, but fat equals flavor. Since ground beef is typically lean, it doesn't hurt to get the 80% lean instead of the 95% lean. The flavor and moisture payoffs are so worth it. Second, make sure to knead the mixture well so that the steak doesn't crack when it's cooking. When it cracks, all that moisture seeps right out. Lastly, once you've finished browning the patties, steam with sake so that they continue to cook without dehydrating.
For the prep, heat up a pan on low heat and small dice an onion. Coat the pan with oil and sweat the onions with a pinch of salt. Sweating is the opposite of browning. The goal is to cook down the onion until it's soft and tender and release the moisture. The salt helps to draw out the moisture. Unlike browning, stirring is recommended to lower the temperature. Sweat the onions nice and slow until translucent and then reserve to cool down to room temperature. Mix the panko (Japanese breadcrumbs) with the milk and let sit to create a panade.
Mix the onions, panade, ground beef, and egg and season the mixture with salt, pepper and nutmeg. Knead the mixture well with your hands to prevent the steak from cracking while cooking.
Form flat round patties and hollow out the center (as pictured above). When it cooks, the meat puffs in the center so this helps to keep the final product even.
Brown each patty on both sides and then pour in the sake and put the lid on and steam for 8-10 minutes until the liquid runs clear. Reserve the hamburg steaks and create a sauce with the remaining sake by whisking in ketchup and Worcestershire sauce. Plate and enjoy!