Salmon & herby potato coulibiacs

• potato↗600g g

  thinly sliced

• large onion↗1

  thinly sliced

• olive oil↗1 tbsp tbsp
• double cream↗100ml ml
• crème fraîche↗100ml ml
• chopped parsley4 tbsp tbsp
• chopped dill4 tbsp tbsp
• zest 1 lemon
• 2 x 375g packs all-butter puff pastry
• a little flour

  for dusting

• side of salmon↗650g g

  skinned and pin-boned, cut crossways into 3cm slices, then cut in half lengthways to get thick fingers

• egg↗1

  beaten

Step-by-step instructions

1. 1

   Heat oven to 180C/160C fan/gas 4. Par-boil the potato slices for 2-3 mins. Drain and set aside in a large bowl.

2. 2

   Gently fry the onion in the oil for 10 mins until lightly golden. Cool slightly, then stir in the cream, crème fraîche, herbs, zest and plenty of seasoning. Pour over the potatoes and mix very gently.

3. 3

   Roll out one pack of pastry on a lightly floured surface to a 35 x 35cm, then lay on a large baking sheet. Pack ¼ of the potato mixture down one side of the pastry, leaving a 5cm border. Arrange ½ of the salmon on top to cover the potato. Cover the salmon with ¼ of the potato. Brush the pastry all the way round with beaten egg and fold over the pastry. Trim the edges and crimp with your fingers, or seal with a fork. Make decorative fish for the top, if you like.

4. 4

   Roll out the remaining pastry and repeat the process, using up the rest of the potato and salmon. Chill for 30 mins.

5. 5

   Brush the pastries all over with beaten egg. Bake for 40 mins. Leave to rest for 10 mins if serving hot, or serve cold.