Preheat the oven to 450°F. Line a baking sheet with parchment paper and keep ready.
Heat 1tbsp oil in a pan, add onions, green chili and ginger+garlic paste. Cook till the onions turn translucent and are slowly getting brown around the edges, about 4~6 minutes.
Next add the mixed veggies and potato. Mix well and cook covered for 5 minutes.
Stir in the red chili powder, salt and garam masala. Mix well and cook for 2 minutes. Turn off the heat and sprinkle the chopped cilantro.
Let the curry cool for 5~10 minutes.
In the meantime, roll the puff pastry out slightly. Then cut it into 2 halves and then each half into thirds to make 6 puff pastry rectangles.
Place 1~2tbsp of the curry on one half of the rectangle. Brush some water along the corner of the puff pastry and pull the pastry over the curry to cover it completely. Pinch the edges to seal. Using a fork pinch the edges even more.
Repeat with the remaining pastry. Place the filled pastries on the prepared baking sheet.
Bake in the preheated oven for 10 minutes or until golden brown. Serve hot with ketchup.