Courtesy of Kristen Eppich.
Rinse quinoa then add to a pot with 1 1/2 cups water. Bring to a boil then reduce heat and simmer, covered, until tender, 8 to 10 minutes. Drain if needed then transfer to a large bowl to cool.
Combine mushrooms with carrots, onion and garlic in a food processor or mini chop. Pulse until finely chopped.
Heat a large skillet over medium-high. Add chili oil, then vegetable mixture. Cook for 5 minutes, or until vegetables are tender.
Stir into quinoa with ½ cup feta, egg, rice flour and salt. Season with pepper.
Refrigerate for 30 minutes or until chilled though.
Heat a skillet over medium heat. Add vegetable oil. Working in batches, spoon ½ cup portions of quinoa mixture into pan and shape into a patty. Cook for 3 minutes per side, or until golden and heated though. Repeat with remaining mixture.
Place burgers on toasted buns. Top with remaining feta and black olives.