Heat the olive oil in a large pan and add onion, garlic, rosemary, carrots and celery and sauté for 5 minutes.
Add bay leaf.
Add the tomato paste to the roast and deglaze with hot water. Add the lentils and cook over medium heat for 30 to 40 minutes. If necessary, add more water or vegetable stock. Add the salt to the first end. This makes the lenses softer faster.