Heat the olive oil in a large heavy-bottomed pot over medium heat until shimmering and fragrant.
Add the chopped onion and sauté until translucent and soft, about 5 minutes. The onions should turn a light golden color and emit a sweet aroma.
Toss in the minced garlic and ground cumin, stirring constantly for about 30 seconds until fragrant and slightly toasted, filling your kitchen with a warm, smoky scent.
Add the diced carrots to the pot, stirring to coat them with the aromatic mixture. Cook for another 5 minutes until the carrots start softening and release a subtle sweetness.
Pour in the vegetable broth and add the crushed tomatoes. Stir well, bringing everything to a gentle simmer. Let it bubble softly for about 10 minutes, watching the rich red color deepen and the flavors meld.
Stir in the rinsed lentils, then reduce the heat to low. Cover loosely and let the stew simmer gently for 25 to 30 minutes, until the lentils are tender and the mixture thickens, with the vegetables melting into the broth.
Check the seasoning and add salt and pepper to taste. If the stew has thickened too much, stir in a splash of broth or water to loosen it up.
Remove from heat and let sit for 5 minutes to allow the flavors to deepen. The stew should look hearty with plump lentils and tender vegetables, with a fragrant aroma inviting you to try it.
Spoon the hot stew into bowls, garnish with fresh herbs if desired, and enjoy the comforting, rustic flavors of this wholesome dish.
