Start by peeling and chopping the carrots into small, even pieces. This helps them cook evenly and makes blending easier later on.
Rinse the lentils thoroughly under cold water until the water runs clear, then set aside.
Heat the olive oil in a large heavy-bottomed pot over medium heat until it shimmers. Add the diced onion and cook, stirring occasionally, until it turns translucent and fragrant, about 5-7 minutes.
Add the minced garlic to the pot and cook for another 30 seconds, stirring constantly until fragrant but not browned.
Stir in the chopped carrots along with the ground cumin and coriander. Cook for 5 minutes, stirring occasionally, until the carrots start to soften and the spices release their aroma.
Pour in the vegetable broth and add the rinsed lentils. Bring the mixture to a gentle boil, then reduce the heat to low, cover partly, and simmer for 25-30 minutes until the lentils are tender and the carrots are very soft.
Check the soup — the lentils should be breaking down slightly and the carrots very soft. Use an immersion blender directly in the pot or transfer the soup in batches to a blender, blending until smooth and velvety.
Taste the soup and adjust the seasoning with salt and pepper. If you like, add a squeeze of lemon juice for brightness.
Let the soup sit off the heat for 5-10 minutes so the flavors can meld together beautifully.
Serve the soup hot, drizzled with a little olive oil or garnished with fresh herbs if you like. Enjoy the silky, nourishing bowl of comfort you've created!
