For Tart Shell: Combine flour, corn starch, sugar and salt in medium bowl. Cut in butter using pastry blender or two knives until coarse crumbs form. Combine yolk and 2 tablespoons ice water; stir into flour mixture. Add enough remaining water, 1 teaspoon, at a time until dough is moistened and can be formed into a ball.
Roll dough into a 12-inch circle on a lightly floured surface. Fit dough into a 8–inch tart pan pressing into side of pan. Trim excess crust as needed. Prick bottom of crust with a fork. Place in freezer for 30 minutes.
Preheat oven 375°F. Line the tart shell with a circle of baking parchment and fill with baking beans then blind bake for 10 to 12 minutes. Remove the baking beans and parchment, return the tart to the oven for 5 minutes until lightly golden and dry to touch. Remove from oven and reduce oven temperature 325°F.
Beat the eggs and egg yolk with the sugar, then stir in the cream until smooth. Stir in the lemon juice and zest mix well. Pour mixture in tart shell. Bake for 25 – 30 minutes or until liquid has set. Remove from oven place on wire rack and let cool for 30 minutes.