Truffle Potato Gratin
Layers of thinly sliced potato and caramelised onion, baked in a truffle-scented cream sauce and finished with melted Gruyère — an indulgent side that's just as at home on a special-occasion table as it is alongside a Sunday roast.
Serves 6–8 · Average · Prep under 2 hours · Cook under 2 hours
Ingredients
- 1 tbsp butter, for the dish
- 1.3kg potatoes, thinly sliced
- 3 tsp salt, divided
- 1 tbsp olive oil
- 1 tbsp truffle oil, plus extra to finish
- 2 yellow onions, sliced
- ½ cup (120ml) chicken broth
- 1½ cups (360ml) cream
- 1 bunch fresh thyme, sprigs reserved for garnish
- 2 bay leaves
- 1½ cups (150g) shredded Gruyère
- ¼ cup (60g) crème fraîche
- Salt and pepper, to taste
- Chopped chives and thyme leaves, to garnish
- Flaky sea salt, to finish
Method
- Preheat the oven to 200°C and butter a 22cm Le Creuset casserole. Slice the potatoes about ⅛-inch thick and layer them into the dish, seasoning lightly with salt between each layer.
- Heat the olive and truffle oils in a pan and cook the onions with 1 tsp salt until deeply golden, 20–30 minutes.
- Deglaze the pan with the chicken broth, then stir in the cream, thyme and bay leaves. Simmer for 5–6 minutes until it thickens slightly. Discard the herbs and stir through 1 cup of the Gruyère until melted.
- Let the sauce cool a little, then stir through the crème fraîche and season to taste.
- Pour the sauce over the potatoes, then scatter over the remaining Gruyère and the caramelised onions. Bake for 45 minutes to 1 hour, until golden and the potatoes are tender.
- Rest for 15 minutes before serving, garnished with thyme, chives, flaky salt and a final drizzle of truffle oil.
Recipe adapted from Le Creuset New Zealand.
