2) Working from the short ends, fold each end halfway to the centre. Then fold each side again towards the centre until the folded edges almost touch. Fold one side over the other and press lightly. Place on a baking sheet lined with greaseproof paper.
3) Repeat the entire instructions for the second sheet of puff pastry using the remaining ingredients. Cover with cling film and chill for at least 45 minutes.
4) Meanwhile, preheat the oven to 200C/Gas mark 4. Cut the prepared rolls of puff pastry in 1cm thick slices and place them face up 5cm apart on baking trays lined with greaseproof paper. Bake for 14 minutes, until golden brown. Serve warm.
1) Place the walnuts, pine nuts and garlic in the bowl of a food processor fitted with a steel blade. Process for 30 seconds. Add the basil leaves, salt, and pepper.
2) With the processor running, slowly pour the olive oil into the bowl through the feed tube and process until the pesto is finely pureed. Add the Parmesan and puree for a minute.
3) Serve, or store the pesto in the refrigerator or freezer with a thin film of olive oil on top.