Start by preparing all your ingredients. Slice the onion and bell peppers, mince the garlic, and chop the green onions.
In a large pot, boil water and cook the rice noodles according to package instructions until al dente. Drain and set them aside, adding a splash of oil to prevent sticking.
In a large skillet over medium-high heat, add the ground beef. Cook until browned, breaking it apart with a spatula, which should take about 5-7 minutes.
Drain excess fat if necessary.
To the browned beef, add the sliced onion, minced garlic, and bell peppers. Sauté for another 5 minutes until the vegetables are tender yet vibrant.
Stir in the soy sauce, oyster sauce, brown sugar, salt, and pepper, mixing thoroughly.
Add the drained noodles, tossing everything to ensure the noodles are evenly coated in the sauce.
Remove from heat and transfer to a serving plate. Garnish with chopped green onions and enjoy your delicious Mongolian Ground Beef Noodles!
