Boil the potatoes for 12-15 minutes until tender. Drain and roughly mash - keep some texture, do not make it completely smooth.
Heat the oil in a frying pan over medium heat. Add the onion and cook for 5 minutes until soft.
Add the garlic, ginger, curry powder, turmeric and chilli flakes. Cook for 1 minute until fragrant.
Stir in the frozen peas and cook for 2 minutes.
Remove from heat and combine with the mashed potatoes and mango chutney. Season with salt.
Preheat the oven to 200C. Roll out the pastry and cut into 4 equal squares.
Place a generous scoop of filling on one half of each square. Brush the edges with beaten egg, fold over and crimp with a fork to seal.
Place on a baking tray, brush with beaten egg and bake for 20-25 minutes until golden.