How to Make It
Combine 1/2 cup water and yeast in a medium bowl. Pour warm milk and remaining 1 1/2 cups water into a large bowl. Stir in yeast mixture. Weigh or lightly spoon flour into dry measuring cups; level with a knife. Add 9 ounces (about 2 cups) flour to yeast mixture, stirring in one direction until smooth. Add salt. Stir in remaining flour, 1/2 cup at a time, until dough is too stiff to stir but still soft. Place dough on a lightly floured surface. Knead 5 minutes or until soft and smooth, dusting with flour as needed. Place in a large bowl coated with 2 teaspoons olive oil; cover with plastic wrap. Let rise in a cool place 8 hours. Punch dough down. Cover; refrigerate overnight.
Divide dough in half on a lightly floured surface; cover one half with a damp cloth. Divide remaining half into 9 (5 1/3-ounce) pieces; shape each into a ball. Repeat with remaining dough half. Let stand 20 minutes.
Place 1 or 2 griddles or cast-iron skillets on grill; heat to medium.
Shape each dough ball into a 9- x 7-inch oval; layer between parchment paper coated with cooking spray. Cook breads on griddle coated with cooking spray 2 minutes or until golden, turning once.