1 kg/2lb 4oz baking potatoes, peeled and placed in a bowl of cold water to prevent them from browning (use floury potatoes such as Russet, King Edward, Maris Piper or Desiree)
1 tbsp garlic infused oil
500ml/17½fl oz lactose/dairy free double cream (you may need a bit extra)
salt and freshly ground black pepper
Preheat the oven to 160C/320F/Gas 2.
Slice the potatoes into thin slices, about 3mm/⅛in thick. Place the slices into a bowl as you cut them.
Season the potatoes, to taste, with salt and freshly ground black pepper.
Mix the garlic infused oil into the lactose/dairy free cream
Pour the garlic infused oil and lactose/dairy free cream over the potatoes and mix well again.
Place the potato slices into the gratin dish. They should come to just below the top of the dish.
Press the potato down with the back of a spoon or your hands so it forms a solid layer.
The cream should come to just below the top layer of potato (top up with more lactose/dairy free double cream if necessary).
Place the potatoes in the oven and bake for 1-1½ hours, or until the potatoes are completely tender.
(If the cream looks like it's splitting, your oven is too hot, so turn it down a bit.)
Recipe adapted from: Good Food