1: Sieve 125 g flour and 125 g chestnut flour together into a mixer bowl. Add 125 g butter, 125 g sweet chestnut purée (crème de marrons), 1 egg and 30 g ground hazelnuts.
2: Knead until the dough is evenly mixed.
3: Transfer the dough onto a sheet of baking paper.
4: Lay a second sheet of baking paper on top and roll out the dough with a rolling pin to about 1/4 inch (1/2 cm) thick. Refrigerate for at least 1 hour.
5: After cooling to firm up the dough, put the dough back on the worktop, remove the top paper and dust with flour.
6: Flip the dough over onto the floured side and remove the other paper.
7: Finish rolling out the dough to the desired thickness.
8: Preheat the oven to 320°F (160°C). Cut out in whatever shapes you like; here they are squares just over 1" inch (3 cm).
You can easily vary the quantity of chestnut flour, which has a slightly bitter flavour. If you reduce it, increase the wheat flour by the same amount to compensate. The dough can be made the day before and refrigerated until needed.