Combine 1 1/2 cups sugar, cornstarch, and salt in a large, heavy saucepan; mix well. Gradually add water and lemon juice, stirring until mixture is smooth.
Beat egg yolks until thick and lemon colored; gradually stir into lemon mixture. Add butter. Cook over medium heat; stir constantly until thickened and bubbly. Cook 1 minute, stirring constantly. Remove from heat; stir in rind and food coloring. Pour into prepared pastry shell.
Combine egg whites (at room temperature) and cream of tartar; beat until foamy. Gradually add remaining sugar, 1 tablespoon at a time, beating until stiff peaks form. Spread meringue over filling, sealing to edge of pastry. Bake at 350° for 12 to 15 minutes or until golden brown. Cool to room temperature.