In small bowl, dissolve yeast in warm water. Let stand about 5 minutes, stirring occasionally, until yeast comes to top of water. Meanwhile, in large bowl, mix 3 cups of the flour, the salt and sugar.
Stir yeast mixture into flour mixture, using wooden spoon, until flour is moistened. Stir in oil. Shape dough into a ball, using hands. (Dough should be soft and slightly sticky. If dough is too wet, work in small amounts of flour until dough holds together.)
Place dough on lightly floured surface. Knead 10 to 12 minutes or until dough is smooth and springy. Grease large bowl with shortening; lightly flour. Place dough in bowl, turning dough to coat all sides. Cover and let rise in warm place about 40 minutes or until dough has doubled in size. Dough is ready if indentation remains when touched.
Gently push fist into dough to deflate. Place dough on lightly floured surface. Divide dough in half; shape each half into a ball. Cover and let rise on surface about 40 minutes or until dough has doubled in size.
Grease 2 large cookie sheets with shortening; lightly flour (or spray with cooking spray; do not flour). Stretch 1 ball of dough into 18x6-inch rectangle by pulling edges away from each other. (If dough is sticky, dust lightly with flour while stretching.) Place diagonally on cookie sheet. Gently flatten dough with fingers until about 1/2 inch thick. Repeat with remaining dough. Cover and let rise about 30 minutes or until dough has doubled in size. (Top will be uneven and bumpy.)
Heat oven to 375°F. Dust loaves lightly with flour. Bake 25 to 35 minutes or until loaves are golden brown and sound hollow when tapped. (If necessary, cover and refrigerate 1 loaf while the other loaf bakes.) Remove from cookie sheets to wire racks; cool.