Steps
1. Rinse the quinoa under cold water, then cook it according to package instructions (usually 2:1 water to quinoa ratio). Set aside.
2. In a skillet, heat olive oil over medium heat. Add the sliced onions and salt, cooking until the onions are soft and caramelized (about 10-15 minutes).
3. Add the sliced mushrooms to the skillet and cook for an additional 5-7 minutes until they are tender and golden.
4. Stir in the black pepper and balsamic vinegar, cooking for another 2 minutes to combine the flavors.
5. Serve the caramelized onion and mushroom mixture over the cooked quinoa, garnishing with fresh parsley if desired.