Prepare your pie crust according to recipe or package directions. Ensure it’s pre-baked and ready to hold the luscious filling.
Once the crust is ready, drop the oven temperature to 350 degrees Fahrenheit. This will ensure that the filling cooks perfectly without burning.
In a large saucepan, stir together the sugar and flour. This mixture will provide the base for the filling, so make sure it's well combined.
Separate the eggs, placing the whites in a large mixing bowl for the meringue. The yolks will go into the filling mixture.
Add the 3 egg yolks and sour cream to the sugar and flour mixture in the saucepan. Mix until combined, then stir in the raisins to distribute them evenly.
Cook over medium heat, stirring constantly until the mixture begins to simmer. Simmer for about 4 to 5 minutes until it starts to thicken. You’ll notice it bubble slightly, indicating that it’s ready.
Turn off the heat but leave the mixture over the warm burner to keep it warm. This will help incorporate the egg whites later.
Add the cream of tartar to the mixing bowl with the egg whites. Beat with an electric mixer on medium speed until really frothy, which usually takes a couple of minutes.
Start adding the granulated white sugar a little at a time while beating the egg whites. Once all of the sugar is added, turn the mixer to high speed and beat until the meringue is glossy and holds stiff peaks. This means it will stand up tall on its own!
Spread the warm raisin filling mixture into the pre-baked pie crust. Smooth it out evenly. Spoon the meringue over the top of the filling, ensuring to spread it all the way to the edges of the pie to seal it in.
Finally, bake at 350 degrees Fahrenheit for about 15 minutes. You want the meringue to turn golden brown. After baking, cool at room temperature for 1 hour, then chill for at least 3 hours before serving.
Serve chilled or at room temperature to enjoy the best flavor and texture.
