Heat the olive oil in a large pot over medium heat. Add the onion, carrots, and garlic. Cook for 5 minutes until the onion softens.
Stir in the sliced mushrooms. Cook for another 5 minutes until they release their liquid and start to brown.
Add the lentils, vegetable broth, rosemary, and thyme. Bring the mixture to a boil, then reduce to a simmer. Cover and cook for 25 minutes.
Stir in the white beans and chopped kale. Simmer uncovered for 10 more minutes until the lentils are tender and the kale wilts.
Season with salt and black pepper. Serve hot.