My family really enjoyed this gratin. You can make this a purely vegetarian by not adding the bacon and or using a cream substitute. Prep time: 15-20 mins Cooking time: 50 mins Ingredients (serves 4 people as a main dish or 6-8 people as a side dish): A splash of olive oil 2 rashers of smoky bacon (optional) 1 large onion and/or leek, finely chopped 3-4 garlic cloves, finely chopped 500g root vegetables (swede, celeriac, Jerusalem artichokes, parsnips, even potatoes), finely sliced* Sea salt and freshly ground pepper A pinch of ground cloves or a handful of thyme leaves 1 mug of double or luxury pouring cream ½ mug of vegetable or chicken stock, or water A handful of oats 1 mug of breadcrumbs A handful of nuts (chestnuts, if you can), chopped A nugget of butter A handful of grated cheese (optional) *Swede, celeriac and other big root vegetables need to be peeled and cut into more manageable pieces before slicing. Instructions: Preheat the oven to 190°C/Gas 5. Place a large frying pan o...