Directions

1. Make the sponge: Combine 1/4 cup warm water and yeast in the bowl of an electric mixer; let stand until foamy, about 5 minutes. Add remaining 1/2 cup warm water and flour; using the dough-hook attachment, mix on low speed 2 minutes. The dough will be wet and sticky. Place in a lightly oiled bowl. Cover; let stand at room temperature 24 hours.
2. Make the rolls: In the clean bowl of an electric mixer, combine 1/4 cup warm water and yeast. Let stand until foamy, about 5 minutes. Add 1/2 cup sponge, pulled into small pieces, and 2 tablespoons olive oil; using the paddle attachment, mix on low speed to combine, about 2 minutes.
3. Add flour, salt, and the remaining warm water; mix 1 minute. Switch to the dough-hook attachment, and mix on medium-low speed until dough is soft and smooth, about 6 minutes. (Or knead the dough by hand on a lightly floured surface 15 to 20 minutes.)
4. Turn out dough onto a lightly floured work surface, and knead by hand several times, shaping dough into a ball. Place dough, smooth side up, in a large, lightly oiled bowl, and cover with oiled plastic wrap. Let rise in a warm spot until doubled in bulk, about 2 hours.
5. Brush two 5-by-9-inch loaf pans liberally with olive oil, and pour 1 tablespoon oil into each. Turn out dough onto a lightly floured work surface, and cut into 18 equal pieces (about 2 ounces each). Working with 1 piece at a time, flatten dough with fingertips into a 4-by-5-inch rectangle. Spread with about 1 teaspoon olive paste, roll up tightly, and pinch long edge to seal. Place roll, seam side down, in prepared pan. Repeat this process until you have filled the bottom of pan with rolls (the pan should hold 9 rolls snugly). Repeat process with remaining dough and pan. Cover with lightly oiled plastic wrap; let rise 1 hour.
6. After 30 minutes of rising, preheat oven to 450 degrees. Place a baking stone, if using, in lower third and an empty baking pan on the shelf below.
7. Use a razor blade or sharp knife to make a lengthwise slash on each roll until olive paste is visible. Put pans in oven (placing on stone, if using). Pour 2 cups very hot water into heated pan to create steam; close oven door.
8. Bake until deep golden brown, 30 to 40 minutes. Turn out onto wire racks. (If bottoms and sides of rolls are not dark enough, return to oven, placing them directly on stone or shelf.) Brush tops with remaining tablespoon oil; cool on racks at least 30 minutes before serving.