Step 1

Heat oven to 450°F. Remove pie crusts from pouches. On lightly floured surface, unroll and stack crusts one on top of the other. Roll to 17x12-inch rectangle.

Step 2

Fit crust into 15x10x1-inch pan, pressing firmly into corners and sides. Fold extra crust underneath and slightly on top edges of pan; poke bottom and sides of crust with fork. Bake 7 to 8 minutes or until light golden brown; remove from oven, and cool completely. Reduce oven temperature to 325°F.

Step 3

Meanwhile, in 3-quart saucepan, mix 2 1/2 cups sugar, the cornstarch and salt. Stir in water, lemon peel and lemon juice until smooth. Cook and stir over medium-high heat. Heat to boiling; boil 1 minute, stirring constantly, until mixture is bubbly and thickened. Remove from heat.

Step 4

In small bowl, beat egg yolks with whisk. Gradually beat about 1/2 cup hot mixture into egg yolks. Gradually stir yolk mixture into hot mixture in saucepan. Cook over medium heat, stirring constantly, until mixture starts to gently boil. Cook 2 minutes longer, stirring constantly. Remove from heat and stir in butter; cover and keep warm.

Step 5

In large bowl, beat egg whites, vanilla and cream of tartar on medium speed about 1 minute or until soft peaks form. Gradually add 3/4 cup sugar, 1 tablespoon at a time, beating on high speed about 5 minutes or until stiff glossy peaks form and sugar is completely dissolved.

Step 6

Pour hot lemon filling into baked pie shell. Immediately drop spoonfuls of meringue onto hot lemon filling, and carefully spread meringue to cover top completely, spreading to edge of crust to seal well and prevent shrinkage.

Step 7

Bake 20 to 25 minutes or until meringue is light golden brown and temperature reaches 160°F. Cool on cooling rack 1 hour. Refrigerate 3 to 4 hours or until filling is set. Store in refrigerator.