Add the lentils and 2 cups of chicken broth to a small saucepan. Bring it to a boil, then lower the heat, allowing it to simmer for about 20 to 30 minutes until lentils are tender but still have a slight bite to them. Set them aside.

In a separate pot, bring the water with a pinch of salt to boil. Stir in the brown rice, cover, and reduce the heat to low. Allow it to simmer for around 30 minutes, or until the rice is tender and all the liquid is absorbed. Cool slightly before setting aside.

In a large soup pot, combine the cooked lentils, rice, the remaining 4 cups of chicken broth, lemon juice, lemon zest, garlic, bay leaf, turmeric, black pepper, and cayenne (if using). Drizzle in olive oil, and sprinkle in parsley as well. Bring it to a gentle boil.

Reduce the heat and let it simmer for 10 to 15 minutes.

Stir in the shredded chicken and continue simmering for about 5 more minutes until warmed through.

Remove the bay leaf. Taste and adjust seasoning with more salt, pepper, lemon juice, or turmeric if needed.

Stir in nutritional yeast for an umami boost if desired.

Ladle the soup into bowls, garnishing with lemon slices, extra parsley, and black pepper. Serve warm.