Prepare beef and vegetables - Don't cut beef too small or it'll shrink after cooking.
Sauté the spices- Put the vegetable oil in a large pot over medium heat and add the scallions, ginger, garlic, and red chilies. After that turn the heat to low-medium and stir-fry until light brown and fragrant, about 2 minutes. (Note 1)
Add the onions and fry them until they're translucent, about 2 minutes. This makes the soup sweeter and tastier.
Add the carrots and fry them for 1 minute. Carrots fried in oil will be sweeter and the soup will have the sweetness of natural vegetables.
Add beef shank or beef ribs and fry for 2 minutes. (Note 2)
Add bean paste, soy sauce and sugar to the pot and stir-fry for 2 minutes. Mainly to color the beef and flavor the sauce.
Pour in the water and tomatoes and turn the heat to medium-high until it boils. Reduce the heat to low and braise for at least 1.5 to 2 hours, or until the meat is tender.
It'll have more flavor if you eat it the next day.
For the instant pot beef stew, sauté everything after you brown it. Put it in an instant pot and add water.
Choose the meat/stew option, 45 minutes total. If you like more flavor, you can simmer the beef stew for 1 hour.