Pizze fritte with onions, ricotta and chilli oil

1.Stir 425ml water and yeast in an electric mixer, stir in 380gm flour, then cover with plastic wrap and leave to prove until bubbly (1½ hours). Add 180ml room-temperature water, 1 tbsp oil, sugar, 1½ tbsp fine sea salt flakes and remaining flour, and knead with a dough hook until a smooth, soft dough forms (8-10 minutes; add extra flour if too sticky). Transfer to a lightly oiled bowl, cover with plastic wrap and refrigerate to ferment until doubles in size (12 hours or overnight).

2.For chilli oil, combine ingredients in a small bowl and set aside for 4-5 hours to steep.

3.Heat oil remaining in a saucepan over medium heat, add onions and shallots and sauté until starting to soften (5-6 minutes), then cover and cook, stirring occasionally, until tender (25-30 minutes). Uncover and stir occasionally until onions are dark golden (10-12 minutes), then add vinegar and rosemary and season to taste.

4.Divide dough into 12 pieces. Line a baking tray with baking paper and scatter with semolina. Roll each piece of dough on a lightly floured surface to a 14cm round, then transfer to prepared tray.

5.Preheat grill to high. Heat oil for shallow-frying in a large frying pan over medium-high heat until hot and fry pizza bases in batches, turning once, until golden and cooked through (3-4 minutes), then transfer to a tray. Spread bases with onion mixture, scatter ricotta over, then grill until golden (2-3 minutes). Top with salami, parmesan and lemon rind, drizzle with chilli oil, scatter with rosemary and serve hot.