Peel the pears and cut into small cubes. Cook for 20 minutes in a covered pan with a little water. Blend to obtain a smooth purée and leave to cool.
Pre-heat the oven to 220 °C (Gas 7). Coarsely chop the walnuts and mix together with the flour, brown sugar and butter in a bowl. Work the dough into a ball (add a few drops of water if necessary). Leave 30 minutes in the fridge.
Roll out the dough to about 0.8 mm thick. Place on a baking sheet and bake 10 to 20 minutes in the oven. The biscuit should be golden and still slightly soft. Remove from the oven and immediately cut out circles of biscuit using a round pastry cutter. Cut a smaller circle from the middle of half the biscuits using a smaller pastry cutter to obtain a ring. Leave to cool.
Prepare the caramelised walnuts. Heat the caster sugar in a pan on medium heat until golden and caramelised. Remove from the heat. Add the cubes of butter, stirring quickly, and then add the walnut halves and cook until caramelised. Place the walnut halves on a parchment sheet and leave to cool.
The biscuits need to be assembled at the last minute for a crunchy texture. Spread a layer of pear purée on a circle of biscuit and place a biscuit ring over the top. Place a caramelised walnut in the middle and serve.
Author and photograph: Philippe Barret