For the pie:
In a mixer set on medium speed, beat the egg yolks for about 2 minutes.
In a separate bowl, whisk together the sugar, flour and salt. Slowly add the sugar and flour mixture to the yolks. Beat this mixture until it falls in ribbons from the beater blade or spoon.
Scald the milk, then add it very slowly to the egg mixture while continuously beating. Pour the batter into a saucepan.
Add the butter and cook over medium heat, stirring constantly, until the custard thickens—this will take 3 to 5 minutes. Do not let it boil.
Remove from the heat and stir in the vanilla and raisins. Cover immediately with plastic wrap, being careful not to touch the surface.
For the meringue:
Heat the oven to 325°. Beat the egg whites to stiff peaks. Slowly beat in the sugar and cream of tartar.
While the pie filling is still hot, pour it into the crust. Top immediately with the meringue and spread over the edges. Bake for 20 to 25 minutes until browned. Cool on a rack. Serve warm or at room temperature.