Heat the olive oil in a large soup pot over medium heat. Add the chopped onion and diced carrots, sautéing until they become tender and fragrant, about 5 minutes, with the vegetables softening and the onions turning translucent.
Add the minced garlic, ground cumin, and smoked paprika to the pot. Cook for about 1 minute, stirring constantly, until the spices release their aroma and the garlic turns golden.
Pour in the rinsed lentils, canned diced tomatoes with their juices, and vegetable broth. Stir everything together, bringing the mixture to a gentle boil over high heat.
Reduce the heat to low, cover the pot, and let the soup simmer gently for 25 to 30 minutes. During this time, the lentils will soften, and the broth will thicken slightly, filling your kitchen with a warm, earthy aroma.
Uncover the pot and check the lentils—they should be tender. Taste the broth and season with salt and pepper as needed, stirring well to incorporate the flavors.
Squeeze fresh lemon juice into the soup to brighten the flavors. Stir in chopped parsley for a fresh, herbal finish. If you prefer a creamier texture, mash a few lentils with the back of a spoon or briefly blend with an immersion blender.
Serve the hot lentil soup in bowls, garnished with extra parsley if desired, alongside crusty bread for a comforting meal. Enjoy the rich aroma and hearty texture that make this dish a true soul-satisfier.