English Walnut Tart with Orange Pastry

In my grandparent’s Northumberland cottage garden there was a lovely old walnut tree in the centre of the lawn. The walnuts were picked when they were fresh and green in the summer for pickling and the ripe nuts were harvested in late autumn. I’m very fond of treacle tart and nearly added my recipe for it in this section. However, this recipe combines all of the elements of a treacle tart but with walnuts added to the filling and orange zest in the pastry, which makes for a delectable tart