Step 1

In a small bowl, combine cracker crumbs and sugar; stir in butter. Press onto the bottom and up the sides of a 7-in. pie plate coated with cooking spray. Bake at 325° for 8-10 minutes or until lightly browned. Cool on a wire rack.

Step 2

In a small saucepan, combine the sugar, flour, cornstarch and salt; gradually stir in water and, if desired, food coloring. Cook and stir over medium heat until thickened. Remove from the heat. Stir a small amount of hot filling into egg yolks; return all to the pan, stirring constantly. Bring to a gentle boil; cook and stir 2 minutes longer. Remove from the heat. Gently stir in lime juice, butter and lime zest.

Step 3

Pour into crust. Cool for 15 minutes. Refrigerate for 1-2 hours. If desired, garnish with whipped cream, lime slices and zest. Refrigerate leftovers.