Heat the oil in a 5 quart pot over medium high to high heat; add half the steak in an even layer on the bottom and cook until browned. Use a slotted spoon to transfer the browned steak to a bowl; cook the remaining steak the same way and transfer it to the bowl.
To the pot that you cooked the steak in, add the bell peppers and onion; cover the pot and cook over medium heat until the vegetables start to soften, about 4 minutes, stirring occasionally. Add the garlic and ginger and cook 1 minute more, stirring constantly.
Stir in the broth, soy sauce, rice vinegar, sugar, fish sauce, coriander, crushed red pepper flakes, turmeric, salt, and black pepper. Bring to a boil, and then cover the pot, turn the heat down to simmer, and cook 5 to 10 minutes. Add the cooked beef back to the pot.
Stir in the coconut milk and cilantro or parsley and turn off the heat; taste and add additional salt as desired.
Serve garnished with suggestions above anything you like!