Rinse the lentils thoroughly under cold water until the water runs clear, then set aside.
Peel and finely dice the onion, and dice the carrots into small, even pieces. Mince the garlic cloves finely.
Heat the olive oil in a skillet over medium heat until it shimmers, then add the diced onions and carrots. Sauté for about 5 minutes until the onions become translucent and the vegetables start to soften, filling your kitchen with a sweet, earthy aroma.
Add the minced garlic to the skillet and cook for another minute until fragrant, being careful not to burn it. Stir constantly.
Transfer the sautéed vegetables and garlic to your crockpot. Pour in the vegetable broth, then add the rinsed lentils, cumin, and thyme. Give everything a good stir to combine the flavors evenly.
Cover the crockpot with its lid and set it to low. Let the soup simmer for 6 to 8 hours until the lentils are tender and the broth has thickened slightly, with flavors melded into a hearty, rustic broth.
About halfway through cooking, give the soup a gentle stir. If it appears too thick, add a splash of additional broth or water to loosen it up.
Once the cooking time is complete, check the lentils for tenderness— they should be soft and breaking down slightly, creating a hearty, slightly oozy texture. Taste and adjust salt or pepper if needed.
If you prefer a smoother texture, briefly blend a portion of the soup with an immersion blender until it’s slightly puréed, but keep some chunks for a rustic feel.
Finish by drizzling a little extra virgin olive oil over the soup and serve hot, garnished with fresh herbs or a squeeze of lemon if you like.
