11⁄2 kilograms floury potatoes, peeled (such as Agria)
1 tablespoon finely chopped thyme or rosemary
finely grated zest 1 lemon
1 clove garlic, crushed
1⁄2 cup cream
3⁄4 cup chicken stock
1⁄2 cup freshly grated Parmesan cheese
sea salt and freshly ground pepper
Grease a 20 cm x 5 cm square oven-proof dish. Preheat the oven to 180 ̊C.
Slice the potatoes as thinly as possible, but don’t place in water. A mandolin is perfect for this. Combine the thyme, lemon zest and garlic in a small bowl.
Arrange a layer of overlapping slices of potato in the base of the dish and scatter with a little of the herb mixture. Season. Continue layering with the remaining ingredients, remembering to season each layer. You should have 4-5 layers if the potatoes are sliced very thinly.
Keep a little of the herb mixture back for the top layer. The potatoes should fill the dish but will shrink down during cooking.
Combine the stock and cream and pour over the potatoes. Season, scatter with the Parmesan and remaining herbs and dot with butter. Lay a piece of baking paper over the potatoes then cover tightly with aluminium foil. Bake for 40 minutes, uncover and cook for a further 15 minutes or until the top is golden and the potatoes are very tender.
To make ahead: Cool and refrigerate the cooked gratin. Remove from the fridge 1 hour before reheating and cut into 6 serving portions, leaving the gratin in the dish. Pour over an additional 1⁄4 cup of cream or stock and a little grated Parmesan. Bake uncovered until hot.
Serving suggestion: Serve with a bowl of salad leaves. We used radicchio, witlof and watercress dressed with a classic vinaigrette.