This is the perfect vegetable dish to serve in the middle of the table, hot and sizzling straight from the oven. I really like the strong red cabbage and wine flavours with the spices, which play against the sweet potato and cream. Of course you can try using white cabbage and, instead of red wine, verjuice. You will be surprised by the effect of adding the grated white potato to the cabbage – the starch really does make the juice into a lovely velvety sauce. If the cream you use is too heavy, it will split in the oven during cooking and give you a layer of fat on top of your gratin. Pouring cream is best, but if you have thickened cream, add a little milk to it to make it thinner.