In a large pan, fry the onion in a little butter until translucent. Add the minced meat and white cabbage and sauté. Deglaze with 150 ml vegetable stock and simmer for 10 minutes. Season to taste with salt, pepper and thyme. In the meantime, cook the rice half cooked in 300 ml vegetable stock for 7 minutes. Add the rice with the excess stock to the cabbage, stir in well and season again to taste. Put everything in a baking dish and bake at 175 ° C for 30 minutes. Cover or sprinkle with the cheese and put in the oven for another 30 minutes.