-
1
Bake piecrust according to package directions and let cool; refrigerate until ready to use.
-
2
Meanwhile, add water to a small bowl; sprinkle the gelatin over the water and set aside.
-
3
In a medium saucepan (preferably nonstick), whisk the lemonade, lemon juice, 1/2 cup of sugar, egg yolks, lemon zest, and salt together.
-
4
Place over medium heat and cook, stirring constantly, for about 7-9 minutes or until the mixture thickens enough to coat the back of a spoon (do not let mixture boil or it will curdle).
-
5
Remove from heat; stir in the softened gelatin and immediately pour into a large bowl.
-
6
Let cool for 10 minutes; then refrigerate for 50-60 minutes or just until the mixture turns lumpy (this indicates the gelatin is starting to thicken it).
-
7
In a large bowl, beat the 4 egg whites until soft peaks form.
-
8
Beat in the cream of tartar.
-
9
Gradually add in the remaining 1/2 cup sugar, beating at high speed until the whites are thick and glossy.
-
10
Beat in the vanilla.
-
11
The whites should be firm but not dry.
-
12
Gently fold about one-third of the whites into the lemon mixture.
-
13
Add the remaining whites and continue to fold until evenly blended.
-
14
Transfer the filling into the cooled pie shell and smooth the top with a rubber spatula.
-
15
Cover with loosely tented foil and refrigerate for at least 3 hours or overnight.
-
16
Serve with a dollop of whipped cream and berries on top.
