Heat olive oil in a pot over medium-high heat. 

Add onion, carrots, celery, and potato and sauté them for about 5 minutes until softened. 

Add garlic powder and cook for another minute.

Stir in tomato paste, cumin, salt, pepper, and chilli powder (if using). 

Let it cook for about 2 minutes to deepen the flavour.

Add vegetable broth, water, and red lentils. 

Bring to a boil, then lower to a gentle simmer. 

Partially cover and cook until the lentils and veggies are tender.

Stir in lemon juice and fresh parsley or cilantro. 

Adjust seasoning if needed and serve warm.