Unroll the pastry. Mix together the soft brown sugar and cinnamon and sprinkle it all over the pastry. Use a rolling pin to roll the sugar into the pasty.
Starting from the short ends of the pastry, roll up both ends tightly, until they meet in the middle. Wrap the roll in clingfilm and refrigerate for 30-60 minutes.
Preheat the oven to 200c/400f and line two large baking sheets with baking parchment or a silicone mat.
Take the pastry roll out of the fridge and slice into thin slices - approx 3mm (1/8 inch) thick. Arrange the slices on the two baking sheets - give them room to expand. Shape each one into the shape of a heart. You'll need to unroll the pastry rolls very slightly to make the tops of the hearts, then pinch the bottom of the hearts to make the pointy bit (see photo above).
Place the tray in the oven for 9-11 minutes until the hearts are golden.
Remove from the oven and leave to cool before removing from the trays.
Melt the chocolate in a bain marie (or in a bowl in the microwave in 30-second bursts - stirring in between each burst). Dip one corner of a pastry heart in the melted chocolate, then sprinkle with a few dried rose petals. Place on a tray and leave the chocolate to set before serving.
Nutritional Information is per serving, based on getting 16 palmiers.