Heat 2 teaspoon oil in a medium pot over medium-high heat. Once hot, add the steak pieces in a single layer. Sear the bottom for 1 minute without moving, then flip and cook for another 3–4 minutes until the steak is at least 80% cooked and golden brown. Add 4–5 cups of hot water, bring to a boil, then cover with lid and simmer on low heat for at least 30 minutes.
Prepare the vegetables:
While the steak simmers, dice the onion, carrots, and potatoes. Cut the tomatoes and cabbage into bite-sized pieces, discarding the core of the cabbage.
Sauté the vegetables:
In a large pot or dutch oven, heat 1 tablespoon of oil over medium heat. Add diced onion and sauté for 2 minutes. Stir in the carrots and potatoes and cook for 2 more minutes.
Build the flavor base:
Stir in the tomato paste and ketchup, cook for a minute until fragrant. Add the tomatoes and cook for 4-5 minutes allowing the tomatoes to soften and release their juices.
Combine everything:
Add the cabbages, cooked steak, 1 cup of beef stock (from simmering the beef), and about 3 cups of water (enough to cover the ingredients).
Season and simmer:
Stir in the salt, sugar, black pepper, soy sauce, and bay leaves. Bring the soup to a boil, then reduce the heat, cover and simmer for 25–30 minutes.
Final touches:
Taste and adjust the seasoning with additional salt if needed. Serve the hearty Hong Kong Style Borscht Soup hot with some steamed rice or crusty bread for a complete meal. Enjoy!