Preheat the oven to 200°C (180°C fan)/400°F/gas 6. Lightly grease or line two baking sheets with baking parchment.
Place the flour, baking powder oats, sugar and raisins in a mixing bowl and stir to combine.
Measure the oil in a measuring jug then add the egg and water and beat with a fork to combine. Pour into the dry ingredients and mix together with a wooden spoon.
Place spoonfuls of the dough on the baking sheets allowing plenty of room for the cookies to spread, then flatten slightly with a palette knife.
Bake in the centre of the oven for about 10–12 minutes or until golden. Take care when baking not to over cook the cookies so that they stay nice and chewy. Allow to cool on the baking sheet for a few moments before transferring to a wire rack to cool completely.