Soup does not get any easier than this, and I've made it even better by turning it into an enoki mushroom soup. The broth tastes similar to the ones you get at Chinese hotpot restaurants.
In a medium pot, heat the oil over medium heat until shimmering. Add the ginger and garlic, and cook for 2 minutes.
Add the ground beef and increase the heat to medium-high. Cook until no longer pink, and you start to hear the beef sizzling, about 5 minutes.
Add the tomato paste and cook for another 2 minutes.
Add the chicken stock, sugar, salt, white pepper, vinegar, enoki mushrooms, and scallion whites, and simmer for at least 15 minutes until the enoki mushrooms are soft and have absorbed some of the soup's flavor.
Garnish with the scallion greens and enjoy!
Notes
Tomato paste: This can easily be substituted with a 28-ounce can of diced tomatoes.