Heat the oil in a saucepan over medium heat; add onion, garlic, and pinch of salt. Cook until they being to soften, 3-5 minutes.
Add the mushrooms, carrots, thyme, rosemary, and red pepper flakes; cook, stirring occasionally, until the vegetables begin to soften, about 5 minutes.
Stir in the cornstarch.
Pour in the broth and bring the soup to a boil. Cover and let simmer for 10-15 minutes, or until the vegetables are very soft.
Stir in the coconut milk and cooked quinoa.
Stir in the lemon juice. Season to taste with salt and pepper. Garnish with fresh parsley or grated parmesan, if desired.