Preheat oven to 325 degrees F.

To make the crust, add the graham cracker crumbs, sugar, and salt to a large bowl and stir to combine.
Add the melted butter and stir until well combined and crumbly.
Pour the mixture into a deep dish 9-inch pie pan and spread the crumbs around so that they are evenly dispersed.
Press the crumbs into the bottom and up the sides of the pan. Set aside.

To make the filling, whisk the lemon juice and sweetened condensed milk together in a medium sized bowl. Set aside.

In a large mixing bowl, beat the lemon zest and egg yolks on high until pale and fluffy, about 5-7 minutes.

Add sweetened condensed milk mixture to egg mixture and stir to combine.

Pour the filling into the pie crust and bake for about 25-30 minutes, or until the edges are set and the center jiggles slightly.

Cool on cooling rack for an hour, then refrigerate until firm, 5-6 hours.

To make the whipped cream, add the cream, powdered sugar and vanilla extract to a large mixer bowl and whip on high speed until stiff peaks form.

Pipe whipped cream around the edges of the pie, adding half a lemon slice between each swirl, if desired.

Store pie in the fridge. Pie is best if eaten within 4-5 days.