Preheat oven to gas 6, 200ºC, 400ºF.
Place onion, potato and squash in a pan with just enough boiling water to cover. Lid on bring to the boil and simmer for about 5 minutes to soften slightly. Drain and allow to cool slightly.
Place in a large bowl the cheese, pickle and cooled onion, potato and squash. Combine together. Roll out the pastry and use a bowl to cut around (about 15cm in diameter). Cut the pastry into about 8 rounds (you will need to re-roll).
Brush the edges of the pastry with water. Place a spoonful of the mixture into the centre and fold over the pastry to contain the mixture. Press the edges of the pastry to seal and lightly press with a fork to seal the edges, then pinch the pastry to make a crimp pattern. Repeat making about 8 pasties.
Place on a nonstick tray and brush the edges with beaten egg. Cook in a preheated oven for about 25 minutes until golden and flaky. Remove from oven and allow to cool slightly before serving. Delicious hot or cold!
See more Lunch recipes