By now the quinoa should have soaked up most of the water. Keep simmering until all the water is absorbed, which should take around 15-20 minutes. Once all the water is absorbed, the quinoa should have a whiteish ring around it and the inside should be clear, and mostly not crunchy. If not, you may need to add more water and continue simmering.
Add in the salt and pepper once done. Place the quinoa in a large bowl, then mix 1 cup of the Parmesan, reserving 1/4 cup for garnishing (hot pan + melty cheese = hard to clean).
Plate it up, sprinkle your cheese on for garnish, and enjoy your creamy delicious oniony goodness.