Cream butter and sugar. Add eggs singly and beat until light and fluffy. Add flour and lemon rind.
Put 1/2 dough in well-greased 9" x 13" pan and cover with pie filling. Drop remaining dough over top. Bake at 325°F for 45 minutes or until golden brown. Cool, top with icing.
In a bowl, combine the confectioners’ sugar, water and lemon juice; stir until combined and smooth (mixture will be thick). With a fork or small spatula, drizzle on top of cooled shortbread.