prick well all over with a fork. Bake in hot oven, 425, for 15 minutes or until golden; cool completely on a wire rack Mix 1-3/4 cups of the sugar, cornstarch, flour, and salt in a medium-size bowl. Heat water to boiling in a medium-size saucepan. Lower heat to medium; slowly add sugar mixture, stirring gently but constantly. Cook, stirring constantly, 5 to 7 minutes or until mixture holds a line when cut with a spoon; remove from heat at once. Do not let mixture boil. Beat egg yolks slightly in bowl; stir in 1/2 cup hot mixture; quickly stir back into mixture in saucepan. Cook, stirring constantly over medium heat, for 3 minutes or until mixture thickens. Remove from heat. Stir in lemon rind, juice, butter or margarine until blended. Pour into cool pastry shell. Beat egg whites with lemon extract until foamy, white and double in volume in bowl. Sprinkle in 1/2 cup sugar, 1 Tbsp. at a time, beating all the time until sugar dissolves and meringue stands in firm peaks. Pile onto hot filling, spreading to edge of crust. This keeps meringue from shrinking. Sprinkle with coconut chips, or place them in a pretty pattern on top. Bake in moderate oven, 350 F degrees, 12 minutes, or until peaks of meringue are a golden brown. Cool completely on a wire rack before cutting