The second rise is key to the finished pie’s texture; if baked too soon, the dough will be firm and too chewy. Make sure it feels floppy, with plenty of puffy air bubbles.
- Combine yeast and 1½ cups warm water (105–110°) in a large bowl; let stand until yeast starts to foam, about 10 minutes.
- Mix in 2 Tablespoons of oil, then salt and 2 cups flour.
- Add another 2 cups flour, a cup at a time, mixing until incorporated and a shaggy dough forms.
- Turn out dough onto a lightly floured surface and knead until soft, smooth, and elastic, 10–12 minutes.
- Place dough in a lightly oiled bowl and cover with plastic wrap. Chill 24 hours.
- Coat a 18×13” rimmed baking sheet with remaining ½ cup oil.
- Gently and gradually stretch dough until it reaches the edges of baking sheet. (If dough springs back or is stiff to work with, let it rest 10 minutes before continuing. You may need to let it rest more than once.)
- Cover dough on baking sheet tightly with plastic wrap and let sit in a warm place (but not too warm!—about 70° is ideal for yeast to grow) until it is puffed and full of air bubbles, 30–40 minutes.