In a large pot, saute the chopped onion in olive oil for 3-4 minutes on medium/low heat. Add in the minced garlic, and toss together for an additional minute.
Add in your spices, tomato paste, lentils and carrots/cauliflower rice if using, and stir together on medium heat to 1-2 minutes.
Pour in your vegetable broth and water, cover the pot and bring it to a boil. Once boiling, reduce the flame to low and let the soup simmer for about 35 minutes.
Stir the soup every 10 minutes, and taste along the way to adjust the seasoning. Towards the end, squeeze in about 2 tbsp of fresh lemon juice and mix together.
The lentils break apart with the liquid, so blending is not necessary. If you want a creamier soup, you can use your immersion blender or let the soup cool and blend it in your blender.
Top with your favorite toppings