In a medium bowl, combine the crust ingredients. Mix well until evenly moistened. Press firmly into the bottom and sides of a 9-inch pie plate.
Bake for 8-10 minutes, or until lightly golden. Remove from the oven and cool at room temperature while you prepare the filling. Keep the oven on at 350°F.
To Make the Filling:
In a large mixing bowl, beat together sweetened condensed milk and sour cream with an electric mixer on low speed until smooth.
Add the fresh lemon juice and continue beating on low until fully combined and slightly thickened. Pour the filling over the crust.
Bake for 8-10 minutes. Remove from the oven and cool completely at room temperature before refrigerating for at least 4 hours (preferably overnight).
To Make the Topping:
Beat cold heavy whipping cream and powdered sugar with an electric mixer until stiff peaks form.
Spread the whipped cream over the chilled pie. Garnish with lemon slices and a sprinkle of lemon zest.
Notes
Save Time with Pre-Made Graham Cracker Crumbs: Using store-bought graham cracker crumbs will speed up the process and reduce the number of dirty dishes.
Don’t Mix Up Sweetened Condensed Milk with Evaporated Milk! If you accidentally use evaporated milk, the pie will not set properly. Sweetened condensed milk is thick and sweet, while evaporated milk is much thinner and unsweetened.
Use Fresh Lemon Juice: Freshly squeezed lemon juice will give your pie the best flavor – avoid bottled lemon juice for the best results.