Preheat the oven to 350 degrees F. Put the frozen pie crust onto a baking sheet.
Using a hand mixer beat the cream cheese and sour cream until smooth. Add the pumpkin and beat to combine. Add the sugars, salt, egg, egg yolks, spice and mix well. Stir in the milk and beat and until well incorporated and smooth. Pour the mixture into the pie crust and bake until set, about 40 to 50 minutes. Allow the pie to come to room temperature.
Using a hand mixer beat the egg whites in a very clean glass or stainless steel bowl on high. When the whites are very foamy, begin to stream in about 1/2 of the sugar. Beat until soft peaks form and stream in remaining sugar and pumpkin pie spice. Beat until stiff peaks form. (When the beaters are lifted out of the bowl peaks should remain standing.)
Increase the oven temperature to broil. Using a spatula cover the top of the pie completely with the meringue, making decorative peaks in the meringue. Put the pie back in the oven and broil until the peaks of meringue are golden brown, about 5 minutes.
Remove from the oven and serve.