Heat 2 tablespoons of olive oil in a large stock pot over medium heat. Add diced yellow onion, chopped celery, and sliced carrots. Stir frequently for about 3-4 minutes until soft and fragrant.

Incorporate 3 minced garlic cloves and continue to sauté for 1 additional minute, ensuring the garlic does not brown.

Pour in 6 cups of vegetable stock, followed by 1 cup of red lentils, 2 bay leaves, 1 teaspoon of turmeric, and 1 teaspoon of cumin. Stir to combine.

Increase heat to medium-high to bring to a rolling boil, then reduce heat to medium-low and let simmer for 12-15 minutes.

Remove from heat and blend 2 cups of the soup with an immersion blender until desired consistency is achieved.

Stir in the juice and zest of 1 lemon, along with salt and black pepper. If using, add 2 cups of spinach and cook for 2-3 minutes.

Ladle the soup into bowls, garnishing with cracked black pepper and fresh parsley or cilantro.