preheat oven to 350°. Grate zest from lemons. Set aside zest. Remove and discard pith from lemons. Quarter and seed lemons.
Process lemon quarters, zest, eggs, sugar and lemon juice in container of an electric blender for one minute or until smooth, stopping once to scrape down sides. Add butter; process 30 seconds. Pour into pastry shell.
Bake at 350° for 40 to 45 minutes or until slightly firm in center. Cool on a wire rack. Garnish, if desired with whipped topping and lemon wedges. Makes one nine inch pie.