1 1/2 cups granulated sugar, divided
1/3 cup cornstarch
1 1/2 cups water
3 eggs, separated
1/4 cup Key lime juice (or regular lime juice)
1 drop green food coloring (optional)
1/4 teaspoon cream of tartar
1/2 teaspoon vanilla extract (optional)
1 (6 ounce) prepared graham cracker crumb crust
Lime slices for garnish (optional)

Preheat oven to 350 degrees F.

In medium saucepan, stir together 1 cup sugar and the cornstarch. Stir in water and egg yolks until smooth. Cook over medium heat, stirring constantly, until mixture boils.

Reduce heat and cook 1 minute; remove from heat. Stir in lime juice and food coloring, if desired, until well-blended. Set aside.

In small mixing bowl, beat egg whites with cream of tartar at high speed until foamy. Add remaining 1/2 cup sugar, 1 tablespoon at a time, beating constantly until sugar is dissolved and whites are glossy and stand in soft peaks. (Rub just a bit of meringue between thumb and forefinger to feel if sugar has dissolved.) Beat in vanilla extract, if desired. Pour hot lime filling into crust. Spread meringue over hot filling, starting with small amounts at edges and sealing to crust all around. Cover pie with remaining meringue, spreading evenly in attractive swirls.

Bake for 12 to 15 minutes, or until peaks are lightly browned. Cool at room temperature. Garnish with lime slices, if desired.

Microwave directions: Prepare graham cracker crust in 8-inch glass pie pan, using your own recipe.

In 1-quart liquid microwave-safe measure or bowl, stir together 1 cup sugar and the cornstarch. Stir in water and egg yolks until smooth. Cook on high power, stirring every 2 minutes, about 6 minutes, or until mixture boils. Stir in lime juice and food coloring, if desired, until well-blended. Set aside.

Beat egg whites with cream of tartar, sugar and vanilla, if desired, as above. Pour hot lime filling into prepared crust. Spread meringue over hot filling as above. Cook on high power, rotating quarter turn every minute, until tip of knife inserted horizontally into side comes out clean, about 3 to 3 1/2 minutes. Cool at room temperature. Garnish with lime slices, if desired.