1. Place the yeast and water in a dishpan or large mixing bowl and stir with a wooden spoon. Add the salt, oil, and 3 cups of flour and continue to stir, adding more flour a little at a time, until the dough is easy to handle. Knead for 5 minutes, or until the dough is smooth and shiny. Shape into a ball.
2. Spread a little oil on the bottom and sides of the bowl. Add the ball of dough, then turn it over, oiled side up. Cover and set in a warm spot for about 50 minutes, or until the dough doubles in bulk. Lightly oil a large baking sheet and set aside.
3. Punch down the risen dough and cut in half, then cut each half into 4 equal pieces (for a total of 8). Form each piece into a ball and let rest for 10 minutes. On a floured board, roll out each ball of dough into a ¼-inch-thick circle. (Don’t be concerned if your circles are irregular; the handmade look is part of their charm.)
4. Place the circles on the prepared baking sheet, cover with a towel, and let rise 30 to 40 minutes, or until doubled in bulk.
5. Place in a preheated 475°F oven and bake about 15 minutes, or until the pitas have just started to brown. Remove from the oven and cover the pitas with a clean kitchen towel (to keep them soft as they cool). They will lose their puffiness, but when you carefully split one open, you will find a pouch in the center.