- 225g/8oz plain flour, plus extra for dusting
- pinch salt
- 150g/5½oz cold butter, cut into cubes
- 50g/1¾oz Parmesan (or alternative vegetarian hard cheese), finely grated
- 2½-3½ tbsp iced water
- 10g butter
- 1 onion, finely chopped
- 2 parsnips, peeled and cut into 1cm cubes
- 1 sweet potato, peeled and cut into 1cm cubes
- 2 free-range eggs
- 200ml/7fl oz double cream
- 2 sage leaves, finely chopped
- 1 tsp fresh thyme leaves, plus 12 thyme sprigs to garnish
- 60g/2¼oz Parmesan (or alternative vegetarian hard cheese), finely grated
- 30g/1oz blanched hazelnuts, roughly chopped
- salt and freshly ground black pepper
- Sift the flour and salt into a mixing bowl. Rub in the butter, then mix in the Parmesan and bring together with the water. Wrap in clingfilm and put in the fridge for 30 minutes.
- Preheat the oven to 200C/180C Fan/Gas 6.
- Roll out the pastry on a lightly floured surface to 2-3mm thick. Cut out six circles using an 11cm/4in cutter and use to line six tart tins, rerolling the pastry if you need to. Line each pastry case with baking paper, add baking beans and blind bake for 12 minutes.
- Remove the paper and beans and bake for a further minute. Remove from the oven and reduce the temperature to 180C/160C Fan/Gas 4.
- Meanwhile for the filling, heat the butter in a heavy-bottomed frying pan. Add the onion and cook for 1–2 minutes. Add the parsnip and sweet potatoes and cook, stirring from time to time, for 15 minutes, or until almost cooked through and caramelised. Spoon into the pastry cases.
- Mix the eggs, cream, sage, thyme and half the Parmesan together in a jug and season well. Pour over the vegetables in the pastry cases.
- Sprinkle the hazelnuts and remaining Parmesan over the pastry cases and decorate each one with two thyme sprigs. Bake for 35–40 minutes until golden-brown. Serve.