In a large saucepan over medium heat, warm the oil. Add the onion and garlic and sauté until softened and translucent, about 5 minutes. Add the ground beef, raise the heat to medium-high, and cook, breaking the meat up with a fork, until the meat browns, about 5 minutes. Add the fish sauce.
Spread the kamias over the top of the meat, reduce the heat to medium-l