Peel and wash the carrots. Celery wash, clean. Peel onion. Cut prepared vegetables into fine cubes. Peel garlic and press through a garlic press. Wash thyme, shake dry and pluck leaves from the stalks except for a little bit for garnishing.
Drain the lentils in a sieve. Heat the oil in a pan. Sauté the vegetables for about 5 minutes, turning them over, and add the lentils after 3 minutes. Deglaze with stock, bring to the boil and simmer for about 10 minutes.
Season with salt, pepper, sugar and thyme. Meanwhile prepare the pasta in boiling salted water according to the instructions on the packet. Crumble cheese. Arrange noodles and sauce on plates. Sprinkle with cheese and garnish with thyme.