1Heat oven to 350°F. Break up cookie dough in ungreased 13x9-inch pan. With floured fingers, press dough evenly in bottom of pan to form crust. Bake 15 to 20 minutes or until light golden brown.
2In large bowl, beat eggs with wire whisk or fork until well mixed. Beat in granulated sugar, flour and butter until well blended. Stir in lemon zest and lemon juice. Pour mixture over warm crust.
3Bake 20 to 30 minutes longer or until edges are light golden brown. Cool completely, about 30 minutes. Sprinkle with powdered sugar. With knife dipped in hot water, cut into 6 rows by 6 rows.