Steps

1. Slice 1 onion into wedges. Thinly slice 2 slices worth of ginger.
   🕒 00:00
2. Melt beef fat to taste in a pot and stir-fry the wedged onions until browned. 【This is the secret!】 To retain the onion's texture, it's recommended to remove them at this point.
   🕒 00:37
3. Remove the browned onions from the pot. Do not wipe off the fat remaining in the pot.
   🕒 04:19
4. Boil water in the same pot.
   🕒 04:25
5. Once the water is boiling, quickly blanch 400g of thinly sliced beef.
   🕒 04:53
6. Carefully skim off the scum that rises to the surface as the beef simmers. Roughly skim off the oil as well. 【This is the secret!】 By choosing thinly sliced beef with plenty of fat and connective tissue, such as brisket or chuck roast, you can prevent the meat from hardening during cooking and achieve a tender result. Avoid lean meat.
   🕒 05:07
7. After removing the scum, add 100ml of white wine to the pot and mix lightly to evaporate the alcohol and remove any gamey smell.
   🕒 10:05
8. Next, add 3 tbsp of sugar, the 2 slices worth of thinly sliced ginger (to be removed later), 1 tsp of Japanese dashi stock, and 3 tbsp of soy sauce, and mix lightly.
   🕒 10:57
9. Bring to a simmer again and cook over medium heat for 10 minutes. Simmer uncovered to allow the liquid to evaporate.
   🕒 11:29
10. After 10 minutes of simmering, return the reserved onions to the pot and mix to distribute evenly.
    🕒 11:59
11. To retain the onion's texture, simmer for another 2 to 5 minutes. 【This is the secret!】 The simmering time will vary depending on the pot size and heat level, so taste test to adjust the tenderness of the onions and the concentration of the flavor. Do not cover.
    🕒 12:38
12. Once the taste and onion tenderness are just right, turn off the heat, serve over rice to taste, and it's complete. Remove the ginger before serving.
    🕒 14:28