Cut both ends off of the lemon, cut it in half and remove all the seeds. Slice into thin slices.
Put lemon slices into processor or blender with sugar and lemon juice and purée until liquified.
Add the eggs, cornstarch, dash of salt, and melted butter and blend until smooth.
Pour onto hot crust and bake 25 - 30 minutes, or until filling is not longer jiggly. Cool and cut into bars. Dust with powdered sugar just before serving.