Japanese-Style Loco Moco

Prepare the dashi stock: Place Kombu in 600 grams of Water and let it soak for 30 minutes. Heat the Water over medium-low heat. Just before it boils, remove the Kombu. Bring the Water to a boil, then turn off the heat and add Katsuobushi. Let it steep for 5 minutes, then strain the Dashi stock through a fine-mesh sieve, reserving 200 grams for the gravy.

Prepare the hambagu: Finely chop the Onion and sauté in a small amount of Vegetable oil until translucent and softened. Let the sautéed Onion cool completely. In a small bowl, combine Panko and Milk, letting the Panko absorb the Milk.

In a large bowl, combine Ground beef, cooled Onion, Panko-Milk mixture, 50 grams of Egg, 10 grams of Koikuchi soy sauce, Salt, Black pepper, and Nutmeg. Knead the mixture thoroughly with your hands until it becomes sticky and well combined. Divide the mixture into two equal portions and shape each into a thick, round patty.