Preheat the oven to 170 degrees Celsius (340 degrees Fahrenheit).
Place all the ingredients apart from the water in a food processor.
Adding the water a bit at a time (because you don’t want to add too much), whizz until it forms a mixture that’s easy to stick together but firm enough to roll out easily, and still retaining some texture - you might need to mix it around a few times so that it all blends together evenly.
Transfer this mixture onto a sheet of baking paper.
Place another sheet of baking paper on top of the mixture and use a rolling pin to roll out the mixture until it’s around 5mm (¼ inch) thick - try to roll it into as much of a neat rectangular shape as possible.
Use a sharp knife to slice it into even rectangles - you should be able to make around 26.
Transfer these onto a baking tray lined with baking paper (I had to divide mine between two baking trays).
Bake in the oven for around 15 minutes, until firm to the touch.
Keeps in an airtight container at room temperature for 5 days.
For an oil-free version, the oil can be omitted.The rosemary can be omitted or replaced with thyme.You can add any spices you want.