Cook the cauliflower florets in a large pot of boiling salted water for 6 to 7 minutes, until they are tender, but still firm. Drain cauliflower and set aside. Heat the margarine in a saucepan and add the bread crumbs stirring constantly until the bread crumbs are golden brown. Cook the rice according to package directions. For the gravy, heat the butter in a saucepan. Add the chopped onion, stir until the onion is translucent. Whisk in crème fraîche and cream, cook for 7 minutes. Add in chives and season with the spices to taste. Spoon the gravy over the cauliflower and rice.