Instructions

1. Grind the sundried tomatoes to a powder before anything else. Left in pieces they stay chewy inside a cracker that is otherwise crisp, and each piece is a damp spot.
2. Stir the flax into the water and walk away for an hour. There is no flour in this cracker — the gel the seeds throw is its only structure, and it is not ready until a spoon dragged through leaves a trench that holds its shape.
3. Fold the basil, thyme, tomato powder and olive oil into the set gel. Putting the oil in earlier coats the seeds and slows the gelling down considerably.
4. Spread the mixture on a lined tray at 3 mm and no more, working from the centre outwards. Flax gel is slippery, and a rubber spatula pushes it out more evenly than a knife.
5. Scatter the flaky salt over the wet surface and press it in lightly. That is the only moment it can go on — off a dried sheet it simply rolls into the tin.
6. Dehydrate at 41 °C for 4 hours, then score the firmed sheet into squares and turn the whole slab onto mesh. The setting is low to keep the flax oil from going bitter, so this is a long job rather than a hot one.
7. Give it a further 8 hours at 41 °C, and leave it until a square snaps rather than bends and the underside looks the same as the top. The sheet is often still soft below long after the surface reads dry, so lift a corner rather than trusting what you can see.
8. Keep the crackers in a tin with a tight lid for a fortnight. Ground flax oxidises quickly once the seed coat is broken, and a cracker that smells of paint rather than tomato has gone.