Combine cracker crumbs, sugar and butter; press onto the bottom and sides of a 9-inch pie plate. Bake at 350 degrees for 12-15 minutes. Cool.
Combine sugar and cornstarch. Whisk in the cream and lime juice until smooth; add the butter and cook over medium heat and bring to a boil. Boil for 1 minute. Remove from heat and stir in the lime peel. I like to add 1 drop of green food coloring...makes it prettier. Cool to room temperature; fold in sour cream and pour into crust. Chill. You can top with sweetened whipped cream before serving. Enjoy!!