Boil the beef: After soaking the beef in cold water, pat dry and cut it into bite size pieces, and bring a large pot filled halfways with salted water to boil. Remove the foam as soon as it boils. Simmer the beef for at least 1 hour until very tender. Periodically skimming off any foam that rises to the top.
Meanwhile dice the onions and red bell pepper, grate the carrots, and slice the green cabbage. Sautee in a frying pan for about 5 minutes or until softened, using 1 tbsp of olive oil. Peel the potatoes and cut it into bite-size pieces.
Add vegetables: Once the meat is tender and cooked through, add the sauteed vegetables to the pot. Add 1 can of diced tomatoes, diced potatoes, 2 Tbsp of tomato paste, 2 Tbsp of melted cheese, 2 Tbsp sriracha hot sauce, 1 bay leaf, remaining 2 Tbsp of salt, 1 Tbsp of black pepper and 1 Tbsp of dried oregano and thyme. Bring everything to a light boil. Cook the soup for 30 minutes until potatoes can be easily pierced with a fork.
Serve: Traditionally served with 1 Tbsp of sour cream if desired and crusty bread. The soup develops more flavor when rested over several hours.
