In a bowl, whisk together the flour, salt and baking powder.
Cut the shortening into small pieces and add to the flour mixture.
Using your fingers, rub the shortening with the flour mixture until the texture resembles uncooked oatmeal.
Pour in the water, a third at a time, while mixing the dough with your hand. When all the water has been poured in, gather the dough into a ball and transfer to the work surface. Knead for five minutes until lightly elastic.
Wrap in cling film and leave to rest at room temperature for at least half an hour.