Combine water and quinoa in a medium saucepan. Bring to a boil, reduce to a simmer, then cover and cook for 15 minutes. Remove from heat and let stand, covered, for 10 minutes. Fluff with a fork and set aside to cool.
To toast pecans; place whole nuts on a baking sheet and bake at 350°F, for 7 to 9 minutes (stirring once).
Sauté onions in oil until softened. Add mushrooms, garlic, and spices/seasonings, stirring until the mushrooms are tender, about 5 minutes. Set aside to cool slightly.
In a bowl, beat egg then add in the cooled quinoa, mushroom mixture, and the remaining ingredients. Stir until combined. Scoop 1/2cup of the mixture and form into a ball, and place on a greased baking sheet. Gently press down until you get the desired thickness. Bake at 350°F for 30 minutes.
Notes
The oatmeal acts a binder, to absorb any excess moisture and keep the burger together.