Potato & celeriac gratin
summary：Make this special side a part of an indulgent weekend lunch perfect for friends....
Ingredients
• 600ml thickened cream
• 3 garlic cloves, sliced
• 4 thyme sprigs
• 1 large celeriac, peeled (see note)
• 2 large potatoes, peeled
• 1-2 tablespoons truffle oil (see note)
• 50g grated Gruyere cheese
Method
1. Preheat the oven to 190°C and grease a 1.5-litre baking dish. Place the cream, garlic and thyme in a pan and bring to just below boiling point, then stand for 15 minutes to infuse.
2. Meanwhile, very thinly slice celeriac and potato (a mandoline is ideal). Toss celeriac and potato together, then layer in the greased baking dish, pouring over some cream mixture, drizzling with a little truffle oil and seasoning between each layer, until you have 6-8 layers. Scatter the cheese on top.
3. Cover with a layer of baking paper and a layer of foil, then bake for 45 minutes. Remove the paper and foil, then bake for a further 15 minutes or until tender, bubbling and golden.