In saucepan blend cornstarch and cold water.
Add boiling water and cook, stirring constantly, until clear and thickened.
Beat egg whites until foamy.
Gradually add sugar, beating at high speed until stiff.
Turn mixer to low speed.
Gradually beat in cold cornstarch mixture.
Turn mixer again to high speed and beat well.
Spread on 9-inch lemon meringue or other meringue pie.
Bake in preheated moderate oven (350°F.) for 12 to 15 minutes.