Set your oven to 220C/200C fan/gas 7. Put all the ingredients in a bowl and mix with your hands to combine to a rough dough. If it’s sticky, add a little more flour so it’s nice and smooth.
On a sheet of baking parchment sprinkled with flour, roll the dough out to the thickness of a £1 coin, then use a pizza cutter or knife and cut it into squares.
Brush the squares with a little water and sprinkle with some salt and the 1 tsp chopped rosemary. Prick each square once in the middle with a fork.
Transfer the baking parchment straight onto a baking sheet, separate each square of dough a little, and bake in the hot oven for 12-15 mins or until the crackers are slightly golden. Cool, then store in a tin for up to two weeks.