Rough-Puff Potato and Caramelised Onion Bourekas

Method

1. Mix the flour and the dough share of salt in a bowl. Cut the cold butter into 1.5 cm cubes, add it and just squash the cubes flat with your fingertips (you should still see lumps of butter). Pour in the ice water and bring it together roughly with a fork. Press the shaggy dough flat, wrap and chill for 20 min.

   Add in this stepPlain (all-purpose) flour 120 gUnsalted butter, very cold 90 gIce-cold water 60 mlSalt ¼ tsp

2. Peel the potatoes, cut them into 3 cm chunks and put them in a 18 cm pot with cold water to 2 cm above, plus the potato share of salt. Boil on high heat for 16 min, until a chopstick slides in easily. Drain, then shake the pot over low heat for 30 seconds to steam off the moisture.

   Add in this stepFloury potatoes 200 gSalt ¼ tsp

   high heat

3. Meanwhile, heat the oil in a 24 cm pan and cook the thinly sliced onion slowly on medium-low heat for 17 min, stirring now and then, until deep brown and sweet-smelling. If it starts to catch, add 1 tbsp water and scrape the bottom.

   Add in this stepOnion 1Vegetable oil 1½ tbsp

   medium-low heat

4. Mash the potatoes smoothly and mix in the onion, crumbled feta, pepper and the rest of the salt. Spread on a plate and let it cool completely; warm filling melts the butter in the pastry and kills the layers.

   Add in this stepFeta 40 gGround black pepper 1 pinchSalt ¼ tsp

5. On a floured surface, roll the dough into a 1 cm thick rectangle and fold it in three like a letter. Turn it 90 degrees, roll and fold in three again. Wrap and chill for 20 min, then do two more roll-and-folds (four in all). A marbled look with streaks of butter means it is working.

   Add in this stepFlour for dusting ½ tbsp

6. Dust again, roll the dough to 3 mm and cut 10 cm squares (8 × 10 cm). Put a tablespoon of potato filling in the centre of each, fold into triangles and seal the edges with a fork. Set them on a tray and keep it in the fridge.

   Add in this stepFlour for dusting ½ tbsp

7. Preheat the oven to 210 °C. Beat the egg, brush it thinly over the tops only, and sprinkle with sesame and nigella.

   Add in this stepEgg 1Sesame seeds 1½ tspNigella seeds ¾ tsp

   oven

8. Bake on 1 tray(s) in the oven for 22 min, until risen in flaky layers, deep golden and crisp underneath. If using two trays, swap them halfway. Cool for 5 minutes before serving.

   oven