Pre-bake the Crust
Preheat the oven to 350°F (180°C).
On a floured surface, roll the pie crust to an ⅛-inch (3 mm) thick circle and line a 9-inch (23 cm) pie tin with it. Crimp the edges and brush all over with an egg wash.
Line the pie crust with parchment paper and fill with pie weights. Bake for 20 minutes, then remove the paper and weights and continue to bake until the crust is golden brown, about 10 more minutes. Set aside to cool (keep the oven on).
To Make the Filling
In a small heatproof bowl, combine the raisins and water, and let plump for 10 minutes, then strain and set aside.
Place the egg yolks in a medium, heatproof bowl near the stove. Place another heatproof bowl with a sieve set over it also near the stove.
In a saucepan, add the sugar, cornstarch, cinnamon, and salt. Slowly pour in the sour cream and milk.
Cook over medium-low heat until steaming (about five minutes).
Slowly add the hot mixture to the egg yolks while whisking them constantly.
Return the mixture to the saucepan and continue cooking, stirring constantly, until the mixture has been actively bubbling for 1 full minute.
Pour through the sieve and into the clean bowl. Stir in the raisins and vanilla extract, then pour into the baked pie shell. Let cool for 10 minutes.
To Make the Meringue Topping
In the bowl of a stand mixer fitted with a whisk attachment (or with a handheld electric mixer and a large bowl), whip the egg whites and salt on high speed until soft, foamy peaks form, about 3 minutes.
While the mixer is going, add the sugar, one tablespoon at a time, then continue to beat for about 5 minutes to stiff, glossy peaks.
Pile the meringue on top of the pie, then spread it out a bit to get near the edges.
Bake the pie for 15 minutes, until the meringue is golden.
Let cool on the counter for one hour, then transfer to the refrigerator to set for at least 3 hours and up to overnight.
Store leftovers well covered and in the refrigerator for up to 2 days.