Pre-heat your oven to 220ºC/200ºC fan
Line your baking sheet with a non-stick cooking liner of grease with butter.
Tear the chicken (75g) into smaller pieces with your fingers and put it into a large bowl. Add the sweetcorn (60g), peppers (45g), soft cheese (100g) and oregano (2 tsp) and mix until fully combined.
Dust your work surface with a little flour and then roll out your pastry into a rectangle 2-3mm thick.
Use a knife to cut the pastry into 6 squares (a dinner knife is fine, no need for anything too sharp).
Evenly divide the chicken filling onto the centre of each square of pastry.
Fold the pastry in half over the filling to form a triangle and then push down around the edges to seal in the filling. Use the prongs of a fork to push down the edges a little more to ensure they're sealed and leave a nice pattern.
Place the pasties onto your baking sheet.
Break your egg into a small bowl and beat it with a fork. Using a pastry brush, brush a little egg over the top of each pasty. Use your fork to prick a few holes in the top of each one.
Pop them into the oven for 15-20 minutes, until the pasty is golden brown.
Once cooked remove from the oven, either enjoy them hot (caution they will be very hot so allow them to cool a little) or pop them onto a cooling rack to cool before eating them cold.