Using a cast-iron skillet, heat 1 tablespoon of butter and 1 tablespoon of oil on high heat. Add the beef cubes, but don’t crowd the skillet to avoid steaming the beef. Therefore, you should make sure that you cook in small batches. Make sure that the beef it cooked on both sides, and until brown—this should take around 10 – 15 minutes. If you choose to cook in small batches, transfer the cooked beef to a side plate, and then work on the other batch.
Next, using a large heavy-bottomed pot, heat 1 tablespoon of butter on medium heat, and then add the onion. Next, add 1 tablespoon of olive oil and stir well to ensure that the onion is coated with oil. Add 1 tablespoon of salt after 10 minutes, and then sauté the onion until translucent until tender—this should take around 20 to 25 minutes. If you have plenty of time, you can spend more time until the onions are caramelized—this should take around 40 minutes.
Now, you can add ginger, garlic, tomato paste, and curry powder, and then sauté for around 2 minutes.
Add the beef and wine, and allow the alcohol to evaporate—this will take around 5 minutes.
Add your veggies and then pour the beef broth until the veggies are covered—you don't have to use all of the broth at once. Cover the pot with the lid, and then allow it to boil.
As it continues to boil, skim off the fat and scum from the soup.
Next, add the bay leaf, and then cover the pot using the lid, but leave it slightly ajar—and now simmer until your veggies are tender—this should take around 20 minutes.
As you continue to cook, skim the broth so that you can clean the surface of the broth. You can now add the remaining broth or water—if needed.
When all the ingredients are tender, add the curry roux. Turn off the stove. Using a ladle to add the roux, allow the curry roux to dissolve completely inside the ladle, and then release it to the broth. This will ensure that the undissolved roux will not get into the broth. When you feel that the curry is very thick for your taste, you can add some water to dilute it. Now, you can start to cook using low heat, and stir regularly—be careful to avoid burning the curry.
Add the Worcestershire sauce and grate the apple to add some sweetness.
Simmer while uncovered, and on low heat—stir occasionally, until the curry gets the consistency you need.
For serving, use Japanese rice, with fukujinzuke topping and some daikon if you like it (and have it).