How to Make It
Stir together yeast and warm water in bowl of a heavy-duty electric stand mixer; let stand 5 minutes.
Add bread flour, 1/4 cup oil, and 1 Tbsp. table salt to yeast mixture. Beat on low speed, using paddle attachment, 10 seconds or until blended. Increase speed to medium. Beat 45 seconds or until dough is smooth. Add 1 Tbsp. rosemary. Replace paddle attachment with dough hook; increase speed to medium-high, and beat 4 minutes. (Dough will be sticky.)
Turn dough onto a floured surface, and knead until smooth and elastic (about 1 minute). Place in a greased bowl, turning to coat. Cover dough with plastic wrap, and let rise in a warm place (80° to 85°), free from drafts, 1 hour or until doubled in bulk.
Press dough into a well greased 15- x 10-inch jelly-roll pan, pressing to about 1/4-inch thickness. Cover with a kitchen towel, and let rise in a warm place 1 hour.
Preheat oven to 475°. Press handle of a wooden spoon into dough to make indentations at 1-inch intervals; drizzle with 3 Tbsp. oil. Sprinkle with kosher salt and remaining 1 Tbsp. rosemary. Bake 14 to 16 minutes or until top is light brown. Remove from pan to a wire rack, and cool 10 minutes.