Heat the olive oil in a large pot over medium heat. Add the onion and cook for 4 minutes until it softens.
Stir in the garlic, carrots, and beets. Cook for 5 minutes, stirring now and then so the vegetables start to soften.
Add the lentils, vegetable broth, turmeric, cumin, salt, and black pepper. Stir to combine everything.
Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 30 minutes until the lentils and beets are tender.
Taste and adjust salt if needed. Remove from heat and stir in the parsley just before serving.