Heat the oil in a large frying pan over a medium-high heat.
Add the diced chicken and cook for 5–6 minutes, stirring occasionally, until it changes colour and is nearly cooked through.
Stir in the garlic paste and cook for 1 minute until fragrant.
Add the chopped onion and diced bell pepper, then cook for 3–4 minutes until they begin to soften.
Stir in the spices and cook for 2–3 minutes, allowing them to become fragrant.
Add the frozen sweetcorn and cook for 2–3 minutes until heated through and tender.
Stir in the tomato puree and cook for 1–2 minutes to remove the raw flavour.
Pour in the double cream and stir well. Simmer gently for 2–3 minutes until the sauce thickens slightly.
Remove the pan from the heat, then leave the filling to cool completely before assembling the pasties.
Preheat the oven to 180°C (160°C fan).
Cut each puff pastry sheet into rectangles, making a total of 12 equal pieces. Place the rectangles on a lined baking tray if needed.
Spoon the cooled chicken filling into the centre of pastry rectangle, leaving a small border around the edges.
Sprinkle the grated mozzarella cheese evenly over the chicken filling.
Place another pastry rectangle on top and press the edges firmly with a fork to seal. Cut a few small slits in the top of each pasty to allow steam to escape.
Brush each pasty generously with the egg wash.
Bake for 20–25 minutes, or until the pastry is golden brown, crisp, and cooked through.
Leave the pasties to cool for a few minutes before serving.
