Potato pissaladière

Method

1. First, make the dough. If you have a stand mixer with a dough hook you can do it in that, but it doesn’t take long to make it by hand. In a bowl, whisk together the water, yeast and about 70g of the flour. Leave for 15 minutes until little bubbles appear on the surface.
2. Stir in the remaining flour, olive oil, salt and thyme and either knead with a dough hook until elastic, smooth and glossy about 5 minutes, or turn it out onto a lightly floured surface and knead by hand, about 10 minutes. Brush a clean bowl lightly with oil, place the ball of dough in it and turn it over, cover with a clean tea towel and leave somewhere warm until doubled in size, which should take about an hour.
3. While the dough is proving, cook the onions. Warm the oil in a large, heavy bottomed frying pan over a low heat. Add 2 of the anchovies and break them up a bit with a wooden spoon – you want them to melt into the oil – then add the thyme and bay leaf. Heap in the onions and garlic, sprinkle on the sugar and cinnamon plus a pinch of salt and stir. Cook very slowly, stirring from time to time and more frequently towards the end, until the onions are very soft, golden and almost jammy. This will take about an hour. Fish out the thyme sprigs and the bay leaf.
4. Either boil or steam the potatoes until tender. Let them cool a bit then cut into thin slices.
5. Line a large baking sheet with baking paper. Turn out the dough and stretch it into a rectangle on the baking sheet, measuring roughly 35cm x 25cm. Leave for 15 minutes while you heat the oven to 180°C fan/gas 6.
6. Stretch the dough out a little more on the sheet. Scatter on half of the onions, spreading them out until they almost reach the edge of the dough. Layer the sliced potatoes on top, then cover with the rest of the onions. Scatter on the cheese then the remaining anchovies and finally the olives.
7. Bake for 25-30 minutes, until the dough is golden and the top bubbling. Remove from the oven, slide onto a cooling rack and brush the edge of the crust with olive oil. Serve warm or at room temperature.