Preheat the oven to 200°C.
Boil the pepper, carrots, and squash in a lidded pan for four minutes until tender and drain.
Mix the drained vegetables with the remaining filling ingredients in a bowl and let cool.
Combine the flour, turmeric, and salt in a mixing bowl.
Rub the butter cubes into the flour with your fingertips to reach a breadcrumb consistency.
Add water gradually to form a dough ball, wrap in film, and chill for 30 minutes.
Roll out the pastry to 0.5cm thickness and cut into 7.5cm discs.
Place the filling onto half of each disc leaving a 1cm border.
Brush edges with egg, fold over to seal, and press with a fork.
Brush the tops with egg and bake on a lined tray for 20 minutes until golden.