1.Place the beef into a medium sized bowl and sprinkle salt and pepper, then lightly coat the meat with the flour.
2.In a dutch oven, heat 1 tablespoon oil and 1 tablespoon butter on medium heat. Add the beef in the pan but do not crowd the skillet. Make sure to cook in three batches. Cook the beef on both sides until brown, about 8 minutes. Transfer the cooked beef to a plate and work on the next batch until all the batches are done.
3.Add 1 tablespoon butter to pot on medium heat and add the onion. Add 1 tablespoon oil and stir to coat the onion. Add 1 teaspoon salt after 10 minutes and sauté the onion until caramelized, about 30 minutes.
4.Add garlic, ginger, curry powder, and tomato paste and sauté for 2 minutes. Add the beef and the wine and let the alcohol evaporate, for 5 minutes. Add the carrots, mushrooms, and potatoes then pour the water in until it covers the vegetables (You do not need to use all of it). Add 1 tablespoon Worcestershire sauce and bay leaves. Cover with the lid and bring it to a boil.
5.When boiling, skim off the scum and fat from the top. Cover with the lid but leave slightly ajar, and simmer until vegetables are tender, about 20 minutes. Once in a while, skim the top. Add the leftover water only if it evaporates too much.
6.Turn heat to lowest setting. Add curry roux and stir until dissolved. If the curry is too thick, add water to dilute. Stir often and be careful not to burn the curry.
7.Add milk, 1 tablespoon Worcestershire sauce, and apple. Simmer uncovered on the lowest heat, stirring occasionally, until the curry becomes the consistency you like. Serve immediately.