In a medium saucepan, combine the rinsed quinoa and water. Bring to a boil over high heat.
Once boiling, reduce heat to low, cover, and simmer for 15 minutes or until quinoa is tender and water is absorbed.
Remove from heat and fluff the quinoa with a fork. Set aside to cool slightly.
Heat vegetable oil in a large skillet or wok over medium-high heat.
Add the ground beef to the skillet and cook, breaking it apart with a spatula, until browned and cooked through, about 5 minutes.
Remove the cooked ground beef from the skillet and set aside.
In the same skillet, add the chopped onion and cook for 2 minutes until translucent.
Add the minced garlic and chopped broccoli florets, stir-fry for 4-5 minutes until broccoli is tender-crisp.
Push the vegetables to one side of the skillet. Pour the beaten eggs into the empty side and scramble until fully cooked.
Add the cooked ground beef back to the skillet along with the cooked quinoa.
Pour in the soy sauce, oyster sauce, and sesame oil. Stir everything together until well combined and heated through.
Season with ground black pepper and salt to taste.
Remove from heat and stir in the sliced green onions.
Serve hot.