In large pot or dutch oven, heat oil over medium heat.
Add onions and saute until they begin to soften, about 3 minutes.
Add mushrooms, salt, and red pepper flakes. Saute for 2 more minutes.
Add ginger and garlic. Saute another minute until fragrant.
Add turmeric, lentils, thyme, broth, and water. Bring to boil. Reduce to medium. Cover.
Cook for 15 minutes. Then add the sweet potatoes.
Continue to cook, covered, for about 10 minutes, until lentils and sweet potatoes are soft but not falling apart. If one is finished before the other, turn off burner; food will continue to steam.
Mix in greens. Simmer for 5 minutes.
Add in lemon juice (starting with 1 1/2 tbsp), nutritional yeast, and black pepper.
Taste. Add salt as needed or additional lemon juice for more brightness. Serve.