Boil the buckwheat in salted water or vegetable stock for about 10 minutes, then drain. Divide the cauliflower into small florets, halve them if necessary, then cook them in salted water for about 3 minutes. Mix the buckwheat with the cream, tomato paste, eggs and cheese, season well. Fill the cauliflower into a large baking dish, cover with the buckwheat mixture and bake everything in a preheated oven at 180 degrees (hot air 160 degrees) for about 20-25 minutes.