Heat the oil over medium heat in a large Dutch oven or cast iron pot. Add root vegetables, shallots and garlic, and cook until the vegetables have started to soften and brown, about 8 - 12 minutes. Stir in herbs, salt, pepper and red pepper flakes and cook for another 3 - 5 minutes.
Pour in lentils, tomato, bay leaves, broth, and water, and bring this mixture to a boil. Cover and reduce to simmer for 15 minutes.
Scoop about 1/4 cup of liquid out from the pot and stir in the miso until dissolved. Add back to the pot along and bring the mixture to a boil. Cover and reduce to simmer for 15 minutes.
Remove lid, add quinoa and stir to combine. Bring the mixture back to a boil, recover and reduce to simmer until vegetables are soft, 30 - 60 minutes.
Remove pot from the heat, uncover and add spinach and nutritional yeast (if using), stirring gently to combine. Taste and season with additional salt and pepper if desired.
Serve with a drizzle of olive oil, fresh herbs and grated cashews.