In a medium bowl, add graham cracker crumbs, melted butter and sugar and mix with fork until well combined.
Pour and press crumb mixture down into the bottom and up sides of 8" or 9" spring-form pan.
Chill in freezer while preparing filling.
In a large saucepan, whisk the lemon juice, lemon zest, cornstarch, sugar, egg yolks and almond milk while cooking over medium-low heat whisking constantly, until mixture becomes thick like pudding. Remove mixture from the heat and whisk in the butter until well combined.
Allow mixture to cool and gently stir in sour cream. Add mixture to the graham cracker pie crust and cool in the refrigerator for at least 3 hours before serving.
Optional: Add 1/2 tablespoon of lemon zest to top of pie filling and top individual pie slices with whipped cream before serving.