Preheat oven to 350°F. Lightly greased 9-inch pie pan or 8x8x2-inch pan.
For Lemon Pie: In medium bowl, stir full pouch Meyer lemon filling mix, water and whole eggs together using a whisk until well blended. Set aside.
Stir crust mix and melted butter until crumbly dough forms. Press dough evenly into bottom of pan. Bake 12-14 minutes.
Whisk filling mixture again and pour over hot crust. Bake 26-28 minutes or until center does not jiggle when shaken and top begins to brown.
For Meringue: Using an electric mixer, beat egg whites and cream of tartar on medium speed until frothy. Gradually add sugar, 1 tablespoon at a time, beating on high speed until stiff glossy peaks form. Spread meringue over baked lemon pie. Return to oven and bake an additional 10-15 minutes or until meringue is light golden brown. Serve pie warm, or chill if served as a bar.