To Make Graham Cracker Crust:

Preheat oven to 375 degrees F.  Combine graham cracker crumbs, sugar and melted butter in a bowl  Stir well to combine all evenly.  Pour into a 9-inch pie pan and press crumb mixture to set.  Bake for 6-8 minutes in the preheated oven OR refrigerate for 1 hour to set.*. If baking, remove from oven to cool completely before filling.

To Make Pineapple Filling:

In a medium-sized saucepan, combine crushed pineapple with juice, cornstarch and salt.  Bring to a boil over medium to medium-low heat.  Stir constantly.  Filling is done when it is thick, bubbly, and coats the back of a spoon without dripping off.  Remove from heat.  Stir in unsalted butter, lemon zest and juice.   Let cool completely before pouring into graham cracker crust.  Refrigerate until cold and set.

To Make Stabilized Whipped Cream:**

In a small bowl, stir together Knox gelatin powder and cold water until gelatin is dissolved.  Let sit for 10 minutes.

Using a hand-held or standing mixer, beat cold heavy whipping cream and powdered sugar until soft peaks form.  Place gelatin mixture in microwave for 10-15 seconds or until liquid.  With mixer running on low, drizzle liquid gelatin into cream.  Turn mixer speed up to medium-high and beat cream mixture until stiff peaks form,

Spread stabilized whipped cream on the top of the cooled pineapple filling.   Return to refrigerator to set (about 1 hour) before serving.  Cut into wedges and garnish with a maraschino cherry or toasted coconut, if desired.  Store pie, covered with plastic wrap, for up to 5 days in the refrigerator.