Ingredients:

  • 1 medium russet potato (about 8 oz / 225g), peeled and quartered
  • 1/2 teaspoon fine sea salt (3g)
  • 400g (3 cups plus 2 tablespoons) all-purpose flour, unbleached
  • 350g (1 1/2 cups) water, lukewarm (about 85-90°F / 29-32°C)
  • 1/2 teaspoon active dry yeast (1.5g)
  • 10g (2 teaspoons) fine sea salt
  • 1/4 cup (60ml) extra virgin olive oil, plus more for drizzling
  • 2 tablespoons fresh rosemary leaves, chopped
  • Flaky sea salt, for sprinkling (Maldon is always a winner!)

Instructions:

  1. Boil the potato until tender. Drain well. Mash thoroughly until smooth. Stir in sea salt. Cool to lukewarm.
  2. In a large bowl, whisk together flour, water and yeast. Add mashed potato. Mix until just combined. Cover and let rest for 30 minutes.
  3. Add salt and mix well, using either your hands or a dough hook, for 5-8 minutes. The dough will be very wet and sticky.
  4. Place dough in a lightly oiled bowl, turning to coat. Cover and let rise in a warm place for 2-3 hours, or until doubled in size.
  5. Gently deflate the dough and transfer it to a baking sheet lined with parchment paper or a silicone mat. Gently stretch and press the dough to fill the pan.
  6. Cover the dough loosely and let it rise for another 30-60 minutes, or until puffy.
  7. Preheat oven to 450°F (230°C). Drizzle generously with olive oil. Use your fingertips to create dimples all over the surface of the dough. Sprinkle with rosemary and flaky sea salt.
  8. Bake for 25-30 minutes, or until golden brown and the bottom is crisp.
  9. Let the focaccia cool on the baking sheet for a few minutes before transferring to a wire rack. Drizzle with additional olive oil, if desired. Serve warm or at room temperature.