In large saucepan, combine 1 1/2 cups sugar, cornstarch and salt. Gradually blend in cold water and lemon juice. Stir in egg yolks. Add butter and boiling water. Bring to a boil over medium high heat, stirring constantly. Reduce heat to medium and boil 1 minute. Remove from heat, stir in lemon peel and food coloring. Pour into baked pie crust. Top with meringue.
Meringue - In a large bowl with electric mixer, beat egg whites with cream of tartar until foamy. Gradually add sugar and beat until stiff peaks form.