Preheat your oven to 190°C. Lightly grease a pie dish and set it aside.

Melt butter in a large pan. Add chopped onion and cook until soft and golden.

Add minced garlic to the pan. Stir gently and cook for one minute.

Sprinkle flour over onions. Stir constantly until the mixture looks smooth and thick.

Pour in chicken stock gradually. Stir well to avoid lumps. Add milk next.

Add mustard, thyme, salt and pepper. Stir and simmer until sauce thickens.

Stir chopped turkey and ham into the sauce. Let everything warm gently.

Fold in frozen peas. Cook for two minutes until heated through.

Spoon the filling into the prepared pie dish. Spread evenly.

Line the dish with pastry if needed. Trim edges neatly.

Place pastry sheet over filling. Press edges to seal properly.

Brush beaten egg over the pastry. This gives a golden finish.

Bake for forty-five minutes until pastry looks golden and crisp.

Let the pie rest for ten minutes before slicing and serving.