Step 1

Put the puff pastry on a well-floured surface and bash it with a rolling pin. Usually you need to be quite delicate with puff pastry as it needs to puff up a lot, but for palmiers it only needs to puff up a little. Roll the pastry out into a rectangle about 30 x 35cm/12 x 14in and the thickness of a £1 coin. Spread the tomatoes over the puff pastry and sprinkle over the rosemary.

Step 2

With the shortest end facing you, take both long edges of the pastry and roll them towards each other to meet in the middle. Brush a little egg down the centre to stick the two halves together. Carefully lift into a large baking tray (making sure it will fit in your fridge first) and put in the fridge for at least 30 minutes to chill and harden.

Step 3

Preheat the oven to 200C/400F/Gas 6.

Step 4

Remove the roll from the fridge and, using a very sharp knife, slice it into 1cm/½in thick pieces. Lay each piece on the baking tray, cut-side up, and brush well with the beaten egg, then bake in the oven for 10–15 minutes until puffed up, crisp and golden-brown.

Step 5

Remove the palmiers from the oven and leave to cool on the baking tray.

Step 6

To serve, pile them high on a plate. These are great little canapés for waiting guests.