Place all the ingredients into a food processor and blitz to form a soft dough – it will become quite liquid as the coconut oil heats up. Pour the dough onto a large sheet of cling film, bundle the edges up to form an airtight case around the dough in a rough ball twisting at the top to secure, and place it in a small bowl to prevent it spreading out. Rest the dough in the fridge for 15-25 minutes, until it is firm enough to roll out, but not so hardened that it cracks. (If the weather is cold and your dough is firm enough to roll out immediately after mixing, you can skip this preliminary chilling step, which is only to firm the dough up enough to handle.)

Place the dough onto a sheet of cling film and roughly shape in to a rectangle. Cover with another sheet of cling film and roll it out to 1cm thick using a rolling pin, keeping the edges to a rectangular shape by hand as you go. The reason for rolling it out between two sheets is because in the absence of gluten the dough is quite delicate, and this helps to keep it in one piece before baking.

Remove the top sheet of cling film, and using the blunt edge of a knife, gently slice the dough into approximately 12 rectangles. Replace the top sheet of cling film to prevent the dough drying out, and place it on a baking tray. Refrigerate the dough overnight so that the chestnut flour slowly hydrates and softens, and the ground linseed has time to gel and bind. If you’re in a rush, you can shorten this process to 4-6 hours. You can leave the dough in the fridge ready to bake for up to five days.

Line two baking trays with baking parchment. Take the dough out of the fridge, remove all cling film, and carefully separate the rectangles to leave room to spread whilst baking. I bake roughly six biscuits per tray.

When you are ready to bake, pre-heat a fan oven to 170°C. Bake for 15 minutes, until the biscuits have browned at the edges and turned golden.

When done, leave the biscuits to cool on the trays for a preliminary 10 minutes (the biscuits will fall apart if you try to remove them too early). Then, gently remove the biscuits directly onto wire cooling rack using a palette knife or fish slice, to finish cooling.

They will keep in an airtight tin for a couple of days, but tend to soften with time.