Rinse the lentils under cold water in a fine-mesh strainer, removing any debris. Let them drain in a colander.

In a large pot, heat olive oil over medium heat. Add the chopped onion and sauté for about 5 minutes until translucent.

Stir in minced garlic and grated ginger, cooking for an additional 2 minutes until fragrant.

Add turmeric powder, cumin, coriander, salt, and black pepper. Stir well to let the spices bloom for about a minute.

Add the rinsed lentils and vegetable broth (or water). Bring to a boil, then reduce to a gentle simmer.

After about 10 minutes, stir in diced tomatoes and simmer for another 20-25 minutes until lentils are tender.

Fold in chopped kale or spinach and cook for an additional 5 minutes until wilted.

Remove from heat and stir in lemon juice for a fresh zing. Adjust seasoning if necessary.

Ladle soup into bowls and garnish with fresh cilantro or parsley if desired.