Bari focaccia with cherry tomatoes and olives (Focaccia barese)

1. Boil the potato in its skin until tender, peel it and mash it while still warm.

2. In a bowl, mix the flour and semolina with the dried yeast and sugar, add the potato and lukewarm water, then the salt, and knead for 10 minutes into a soft, sticky dough; cover and leave to rise for 1.5-2 hours until doubled.

3. Generously grease a round tin of about 32 cm (or a 30x40 cm tray) with 4 tablespoons of olive oil, put the dough in and press it out to the edges with your fingers.

4. Halve the cherry tomatoes and press them cut side down into the dough, squeezing out a little of their juice; scatter the olives in between, sprinkle with salt and oregano and drizzle with the remaining oil. Cover and leave to rise for another 45 minutes; preheat the oven to 240 °C.

5. Bake on the lowest shelf of the oven for 25-30 minutes until the base is crisp and golden and the tomatoes slightly charred.

6. Let cool until warm and serve cut into wedges.

Tip: The potato keeps it soft for days; in Bari the bakeries bake it from morning to evening, and the oil in the tin fries the base crisp - the tomato juice gives it its flavour, so don't be shy about squeezing.