Start by rinsing the lentils under cold water until the water runs clear, then set aside. Dice the onion, chop the carrots, and mince the garlic—these will form the flavorful base of your soup.
Heat the olive oil in a skillet over medium heat until it shimmers and you hear a gentle sizzle. Add the diced onion and cook for about 5-7 minutes, stirring occasionally, until it turns translucent and begins to caramelize slightly, releasing a sweet aroma.
Stir in the minced garlic and cook for another 30 seconds until fragrant, filling the air with a savory aroma.
Transfer the sautéed onion and garlic mixture to the crockpot. Add the rinsed lentils, chopped carrots, smoked paprika, cumin, and pour in the vegetable broth. Give everything a good stir to combine the ingredients evenly.
Cover the crockpot with its lid and set it on low. Let the soup cook for 6 to 8 hours, allowing the flavors to deepen and the lentils to become soft and silky.
After the cooking time, open the lid and check the consistency. The lentils should be tender and easily mashable, and the vegetables soft. If the soup looks too thick, stir in a splash of hot broth or water to loosen it up.
Stir in the lemon juice or vinegar to brighten the flavors and add a fresh zing. Taste and adjust salt or pepper if needed.
Give the soup a final stir, ladle into bowls, and serve hot. Garnish with fresh herbs or a drizzle of olive oil if desired for an extra touch of flavor.
