Refresh the sourdough starter at least four hours before mixing. Allow 8–12 hours for the dough to rise, depending on room temperature.
Bari-Style Focaccia with Cherry Tomatoes
Yield 2 focacce (32 cm each)
Method
Boil the potato until tender, peel it and mash it smooth. Refresh the sourdough starter at least four hours before mixing.
Combine the type 0 wheat flour, remilled semolina, mashed potato, salt and refreshed starter in a stand-mixer bowl. Begin mixing at low speed and add the water gradually, using very cold water in a hot room or room-temperature water otherwise. Add the olive oil last. You can also mix and knead by hand in a bowl.
After five minutes at low speed, knead for 15 minutes at a faster setting, until the dough is smooth, elastic and releases from the bowl. If it clings, add a light dusting of flour at the bowl’s edge, taking care not to add too much.
Oil the work surface and turn the dough to coat both sides. Divide it equally into two portions and shape each into a round. Set the rounds close together on a well-oiled tray and leave uncovered at room temperature for 8–12 hours: about eight hours above 20°C, or up to 12 hours at 15–20°C.
Press a round lightly with a fingertip: the dough should spring back. Oil two 32 cm round pans. Place one dough round in each pan, turn it to oil both sides, then stretch it gently with oiled fingers to cover the base.
Break the cherry tomatoes in half by hand so their juice and seeds run onto the dough. Arrange them cut-side down, covering the surface, and add the brined Barese olives. Drizzle with olive oil and season with salt and dried oregano.
Bake in a fully preheated oven at its maximum setting for 20–25 minutes: ideally 270°C, or about 250°C if that is your oven’s maximum. If using a baking stone, place it on the lower rack and preheat it for at least 40 minutes. The baked focaccia should be crisp outside and soft within.
