Preheat the oven to 200C / 180C fan. Place flour and salt in a food processor, add the butter and pulse briefly until the mixture resembles fine crumbs. Stir in the sugar. Add the egg yolks and enough water and process until the dough just starts to come together. Transfer the dough to a lightly floured surface and knead gently into a round. Wrap in cling film and chill for 20 minutes.

Remove the pastry from the fridge and roll out on a floured surface to form a circle large enough to line a 25 cm fluted tart tin. Press the pastry into the sides and base of the tin and trim off the overhang. Prick the base with a fork and chill for a further 20 minutes. Line the pastry case with baking paper and baking beans and bake for 12 minutes. Remove the paper and beans and bake for a further 6-8 minutes until the pastry is crisp and golden. Leave to cool completely.

Reduce the oven temperature to 190C / 170C fan. Place the butter and sugar in a food processor and blend until smooth, add the eggs, vanilla and hazelnuts and blend until evenly combined. Spoon the cream into the pastry shell and press the pear slices well down into the cream. Transfer to the oven and bake for about 40 minutes until firm and golden (cover with tin foil if the pastry starts to get too dark).

Remove from the oven and allow the tart to cool for 30 minutes or so and serve at room temperature with a little crème fraîche dusted with cinnamon.