Peel, wash and cut the carrots into small cubes. Peel and finely dice the onion and garlic. Heat the oil in a pot. Sauté onion and garlic in it. Add the carrots and steam briefly.
Deglaze with 1/4 litre water. Bring to the boil, stir in stock and oregano. Simmer covered for about 5 minutes. Add tomatoes and juice to the carrots. Chop the tomatoes coarsely and simmer open for another 10 minutes.
Cook the pasta in boiling salted water for about 10 minutes until al dente. Drain the noodles and let them drain. Coarsely grate the feta cheese and mix half of it with the noodles. Spread the noodles in a lightly greased casserole dish.
Season tomato-carrot sauce with salt and pepper and pour over the pasta. Spread crème légère as a blob on top. Sprinkle the rest of the feta cheese over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes.
Possibly garnish with oregano.