Roll out the puff pastry on a lightly floured surface to an oblong, about 48×53.5cm (19×21 inches).
Trim the edges neatly.
Mix the caster sugar and the ground spice together.
Brush the pastry very lightly with a little milk.
Sprinkle lightly with some sugar and spice.
Fold the two longest sides to the center of the pastry to meet.
Brush the pastry with a little more milk and sprinkle with more sugar and spice.
Fold the long folded sides to the center again.
Brush the pastry with a little more milk and sprinkle it with the remaining sugar and spice.
Fold the two folded sides together.
Cut the pastry strip into twenty 2.5 cm (1 inch) wide pieces.
Take one of the pastry pieces and turn it on its side on a lightly floured surface.
Flatten slightly with the palm of your hand then roll it out gently on a baking sheet to about 10 cm (4 inches) long ten repeat the process with the remaining pieces.
Refrigerate the palmiers for about 30 minutes.
Brush each palmier with a little milk to glaze, then bake at 230ºC (450º) mark 8 for 20-25 minutes until they are golden brown and cooked.
Transfer to a wire rack to cool.
Whip the double cream with the strawberry purée and icing sugar until thick enough to pipe and fill a piping bag fitted with a star nozzle.
Pipe the cream on 10 of the pastry hearts.
If the strawberries are very large, cut them into slices. If they are small, cut them in half. Leave wild strawberries whole.
Arrange the strawberries on top of the cream, then place the remaining pastry hearts on top of the strawberries at an angle.
Sift icing sugar slightly over the palmiers and serve.
