Shred the cabbage and finely chop the onion. Place them in a bowl and sprinkle the cabbage with salt. In a separate bowl, mix the panko breadcrumbs and milk together.

Cover the bowl with the cabbage and onion loosely with plastic wrap and microwave at 600W for 1 minute 30 seconds. Let cool.

In another bowl, combine the ground meat, microwaved cabbage and onion, the panko-milk mixture, egg, ketchup, soy sauce, Worcestershire sauce, sugar, nutmeg, and salt and pepper. Mix well.

Spread the meat mixture evenly in a heatproof baking dish. Sprinkle the panko breadcrumbs on top and drizzle with vegetable oil.

Bake in a preheated oven at 400°F (200°C) for 25 minutes. If you insert a skewer and the juices run clear, it's done. (Baking time may vary depending on your oven.)