01 -
Preheat the oven to 200C/400F (fan). Line a 22.5cm round, deep pie dish with one pastry sheet, trimming the edges to leave a 1cm overhang. Prick the base with a fork, line with baking parchment, and fill with baking beans. Bake for 10 minutes, then remove the beans and parchment once cool enough to handle.
02 -
Heat the oil and butter in a large saucepan over medium heat until the butter melts. Add the onion and cook for 5-6 minutes until softened. Stir in the flour and cook for 1 minute.
03 -
Gradually add the stock to the onion mixture, stirring continuously to prevent lumps. Add the milk and continue stirring until the sauce thickens and bubbles. Stir in the lemon juice, thyme, black pepper, and parmesan. Mix in the chicken and ham, then remove from heat.
04 -
Fill the pre-baked pastry base with the chicken and ham mixture. Brush the edges of the pastry with egg wash. Top with the second pastry sheet, sealing the edges by pinching. Trim any excess, brush with more egg wash, and pierce small holes in the top.
05 -
Bake the assembled pie at 200C/400F (fan) for 20-25 minutes until golden brown. Slice the pastry lid into portions, spoon out the filling and pastry base, and place the portioned lid on top before serving.