Mix together the graham crumbs, butter and sugar. Press into a 9 inch pie pan and use the bottom of a flat glass or a flat measuring cup to evenly press along the bottom and use your fingers to press evenly along the sides. Set in the fridge until the filling is ready.
Whip cream to stiff peaks and set aside.
In another bowl, use the paddle attachment to beat the cream cheese until smooth. Add sweetened condensed milk, lime juice, and lime zest and mix using the whisk attachment.
Fold in the whipped cream.
Pour into chilled crust and set in fridge for at least 3 hours, or overnight.
Whip cream and powdered sugar together until medium stiff peaks form. You can use a piping bag and star tip to pipe a design on top, or just spread it across with a spatula. Add fresh lime zest, if desired.
Serve and enjoy!
You may have more than enough filling to fill your pie shell. The leftover filling makes a great key lime dip! Let it chill in the fridge for 3 hours and then serve with graham crackers, vanilla wafers, shortbread cookies, or animal crackers.