Grandma Stone's Lemon Meringue Pie

Grandma Stone makes the best lemon meringue pie in the whole world. My mom finally got the recipe from her (I've been begging for it for 10 years!), so I figured I better put it somewhere permanent so it will never get lost.

Grandma Stone's Lemon Meringue Pie

Prepared, baked pie shell

Filling:
1 can sweetened condensed milk
1/2 cup lemon juice
3 egg yolks
1-2 Tablespoons lemon zest

Meringue:
3 egg whites
1/2 teaspoon vanilla
1/4 teaspoon cream of tartar
6 Tablespoons sugar      

1. Mix filling ingredients and pour into pie shell. 
2. Beat egg whites, vanilla, and cream of tartar until soft peaks form. Gradually add sugar until glossy, stiff peaks form and sugar is dissolved.
3. Top filling with meringue.
4. Bake at 350 degrees F for 12-15 minutes, until meringue is golden brown