Grease and line the baking tin with baking paper. Take the first packet of pastry; lightly dust both sides of the pastry with flour (makes it easier to handle).
Line the tin with the pastry; you should have an even overhang of pastry at either end of the tin. Pop this in the fridge while you prepare the filling.
Sauté onion over low heat in olive oil, cook gently for at least 20 minutes until onion is translucent. Add chopped bacon and continue to cook for a further 5 minutes.
Transfer onion mixture to a mixing bowl add the herbs, eggs and cheese together with a good grind of pepper and a sprinkle of sea salt, mix to combine.
Fill the lined baking tray with the filling.
Take the second packet of pastry and cut a lid to fit the top of the pie, allowing for a 2cm border where you will fold over the base pastry to seal with the lid. Place the lid on top of the filling, egg wash a 2cm border then fold over the base pastry to seal in the filling.
Egg wash the top of the pie, cut slits in the pastry to create a star shape.
Bake for 20 minutes at 200c fan-forced (220c non-fan) then reduce the oven temperature to 180c fan-forced (200c non-fan) and continue to bake for a further 20 minutes until golden brown.
Note: Excess pastry can be re-frozen if not been defrosted for more than 24 hours.