1 onion, finely chopped
300驳/10陆辞锄 potatoes, peeled and cut into small pieces
1 tsp English mustard
375g/13 oz plain flour, plus extra for dusting
1 tsp ground allspice
1 pinch sea salt and black pepper
1 tsp garam masala (alternatively use any blend of curry powder)
1 tsp salt
1 tsp ground turmeric
200g/7oz Lancashire cheese, grated
175g/6oz unsalted butter
1 free-range egg, beaten