Preheat the oven to 200C/400F/Gas 6.
Combine the potato, curd cheese, Lancashire cheese and fried onion in a bowl, and season well with salt and freshly ground black pepper.
Cut out 12 x 15cm/6in circles from the puff pastry.
Divide the cheese, potato and onion mixture equally among the centres of six of the pastry circles, leaving a clean edge around each circle.
Brush around the edge of each pastry circle with the egg wash and place another pastry circle on top.
Press down around the edges to create a crimped seal and brush all over with egg wash.
Place onto a greased baking sheet and transfer to the oven to bake for 20 minutes, until crisp and golden-brown.
For the basil buttered vegetables, place the butter and basil into a food processor and blend to combine.
Boil or steam the vegetables until tender, then place into a bowl.
Add the basil butter and mix to melt and coat the vegetables.
To serve, place a pasty onto each of six plates and serve a spoonful of vegetables alongside.