Heat the olive oil in a large pot over medium heat. Add the diced onion and cook for 3 minutes until it softens.
Stir in the minced garlic and ground cumin. Cook for 1 minute until the cumin smells fragrant.
Add the sliced carrots and rinsed lentils to the pot. Pour in the vegetable broth, salt, and black pepper. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 25 minutes until the lentils and carrots are tender.
While the stew simmers, cook the rice in a separate pot according to package directions using 2 cups of water.
Once the stew finishes, taste and adjust salt if needed. Serve the stew over portions of the cooked rice.