1. Heat the oil in a large frying pan.
2. Add in the onions and mushrooms and cook until the onions are soft.
3. Add in the carrots, celery, and spices. Cook until the vegetables are soft.
4. Add in the beans and water. Stir to combine and cook for 4-5 minutes or until the mixture has thickened.
5. Stir in the potatoes and walnuts to combine.
6. Allow to cool before adding to pastry.

Assembly

1. Roll out your pie pastry into 6-inch circles.
2. Add 100 g of filling into the centre of the pastry. Pull half the pastry over the filling and align with the edges of the other half of the pastry, making a half-circle.
3. Using a fork, crimp the edges of the pastry to seal shut. Cut 3 slits on top of each pastry.
4. Brush each pastry with egg wash and bake at 185°C for 25 minutes or until the top is golden brown.