Season beef chunks generously with salt and pepper. Heat oil in a large heavy-bottomed pot over medium-high heat and sear beef until browned on all sides. Remove and set aside.
In the same pot, sauté chopped onions until golden brown, about 8-10 minutes. Add minced garlic and ginger, cooking for another minute until fragrant.
Add potatoes, carrots, and mushrooms to the pot. Stir and cook for 3-4 minutes.
Return seared beef to the pot. Add red wine (or additional stock) and bay leaf. Bring to a simmer, cover, and cook for 45 minutes until beef is tender.
Add beef stock and tomato paste, stirring to combine. Bring mixture to a gentle simmer.
Break curry roux into pieces and gradually stir into the pot until completely dissolved. Add curry powder, grated apple, Worcestershire sauce, and milk.
Simmer uncovered for 15-20 minutes, stirring occasionally, until sauce thickens to coat the back of a spoon.
Remove bay leaf and adjust seasoning with salt and pepper. Serve hot over cooked Japanese rice.