Puff pastry is widely available store bought which is totally fine but its not much extra effort to make it at home. The advantage of homemade is ingredient control: you can make it with nice organic butter and flour or if you're vegan vegan margarine so you don't have to hunt for vegan puff which is quite hard to find. I really think you'll find this much tastier than store bought and when you see how simple it is you'll find its much easier than a trip to the shops.
You need to make this one day in advance of using it. It also freezes very well. This recipe makes a roughly 650g block.
For the puff:300g Bread flour
250g Butter or Vegan Margarine (very cold or frozen)
1 small tsp. sea salt
Ice cold water
Squeeze of lemon (optional)
1) Put the flour and salt in a bowl. Grate the fat into the bowl using the largest of the grating options on the grater.
2) Add the squeeze of lemon. Then using a big metal spoon stir and add enough water in to bring it together but not make it soggy.
3) With you're hands form into a rough ball and place on a floured surface. (Remember hands are pastry's natural enemy- they are warm and make your pastry chewy. Don't handle it any more than you need to.)
4) Roll into a big rectangle about 1.5cm thick.
5) Fold the two sides into the centre as in the picture below.
6) Rest in the fridge for a few minutes. Take it out and place it back on a floured surface long ways. Roll it out again and repeat the process and then repeat again and again and one more time for good luck (3-4 times in total).
7) Fold it again and cover with cling film. Rest in the fridge over night.