Measure the flours.
Dissolve the yeast in the water and set aside for a couple of minutes. Sift flour and salt together into a bowl and stir in the sugar (it is important to mix the dry ingredients first).
Gradually pour the yeast water and the oil into the dry ingredients and mix.
Knead the mixture to make soft dough.
Tip the dough onto a lightly floured surface and knead for 5 to 10 minutes until smooth and elastic. (If you are using a food processor or stand mixer, add the dry ingredients first, then gradually add the liquids. Start at a low speed, and gradually turn up the speed, running the machine for 1 minute. Always stand close to the machine while it is running).
Place the dough into a large bowl dusted with extra flour or greased with olive oil (this will prevent the dough from sticking to the surface of the bowl). Cover the bowl with a damp dish towel and leave to rise in a warm place, free of drafts, for 1 1/2 to 2 hours, or until doubled in bulk. I usually place my dough in an unheated oven to rise.
Punch down the dough. On a floured surface, form the dough into a log. Pinch off the dough to form 4 equal-sized balls (unless otherwise specified in the pie recipe). Flour or grease the bowl again and leave to rise for an additional half-hour.
Flatten each ball with your palm.
Using a rolling pin, roll out each ball of dough into a disc of about 10 in (25 cm) and a thickness of 1/4 in (6 mm).
If you are using a conventional oven, spread the circles onto a baking or crisping pan or place your baking stone on the bottom shelf of the oven before preheating.