This is my favourite contribution to the autumn dinner table, and one that can be served as a hearty side, or as a meal in its own right.
Ingredients - serves 4 - 6
- 1.2kg sweet potatoes
- 400ml double cream
- sprig of rosemary
- 100g Gruyère cheese
- 50g pecans
- Butter, for greasing
- Salt and pepper
Preheat the oven to 200°C/180°C fan/gas mark 6. Grease a 23cm (approx.) pie dish (ceramic is best) with butter. Whatever you do, don’t use a dish with a loose bottom or you’ll be scrubbing your oven floor for weeks.
Peel the sweet potatoes and slice each very thinly – I use a mandolin or a food processor, but it can be done using a knife, with a straight eye and steady hand. After you’ve peeled each potato, rearrange the slices as though you were trying to stick them back together to reform the whole potato. Wedge these bundles into the greased dish randomly and at different angles – treat them as though the potatoes were whole, just pack them tightly into the dish.
Heat the cream in a medium saucepan over a low heat. Add the rosemary with a pinch of salt and pepper. Once the cream comes to a simmer, remove from the heat and leave to infuse for 5 minutes.
Pour the infused cream over the waiting sweet potato. Cover the dish with foil and bake for 45 minutes, then remove from the oven and take off the foil.
Coarsely grate the cheese and roughly chop the pecans, then scatter both cheese and nuts over the baked gratin. Return to the oven for a further 15–20 minutes, until the cheese top is bronzed and the sauce is bubbling. Allow to cool and set for 15 minutes before diving in.