Combine condensed milk, water, salt, milk and butter in a heavy based saucepan and bring to boil over very moderate heat, stirring constantly to dissolve the condensed milk.
Take care not to scorch the milk.
Mix the corn flour and water and stir into the hot mixture.
Stir and cook until thickened and stir in the diced bread.
Simmer gently for 10 minutes and serve piping hot sprinkled with cinnamon or cinnamon sugar.