1. Preheat oven to 200°C fan.

2. Using an electric whisk, cream the butter and sugar until soft and pale.  Add in the eggs, followed by the plain flour, ground almonds and pistachio paste (if using).  Lastly fold in half the chopped pistachios and pomegranates (reserving the other half for decoration).

3. Roll the puff pastry out into two rectangles approximately 30cm x 20cm each in size.

4. Lay the base sheet of puff pastry on a sheet of parchment paper.

5. Leaving a 3cm border around the outer edges, spread jam down the middle length of the pastry.

6. Spoon the filling over the jam.

7. Fold the pastry borders inwards to encase the filling and baste the pastry edges with some egg wash.

8. With the second layer of pastry, overlap three wide ribbons of pastry to create a wide plait.  Lay it over the filled pastry, sealing the sides by pressing the pastry edges together and tucking the pastry underneath at either ends.  Brush the pastry all over with egg glaze.  Transfer the filled plait to the refrigerator for 20 minutes.

9. Bake in the preheated oven for 30-35 minutes (reduce the oven temperature after 25 minutes if the pastry is darkening too much).  Remove from the oven and garnish with the reserved pistachios and pomegranates.

10. Serve warm with whipped cream or ice cream.