How to Make It
Prepare Macaroon Tart Shells, and set aside.
Combine sugar, cornstarch, and lemon rind in a saucepan, and stir well. Gradually add water and lemon juice; stir with a wire whisk until blended. Bring to a boil over medium heat, and cook, stirring constantly, 1 minute. Gradually stir one-fourth of hot lemon mixture into egg; add to remaining lemon mixture, stirring constantly. Cook over medium heat, stirring constantly, 1 minute or until thickened. Pour mixture into a bowl; stir in food coloring, if desired. Place plastic wrap on surface, and chill.
Spoon 1 tablespoon plus 1 teaspoon lemon mixture into each prepared shell. Top evenly with whipped topping and coconut.