Nope, you can't use evaporated milk coz you have to boil the tin of condensed milk UNOPENED until it goes 'toffee-fied', you'd just burn the evap and sugar, else you'd have to stand there constantly stirring over a low heat for over two hours........................look at state of saucepan....go buy condensed milk!!
mercia is right, but you can buy ready made spreadable toffee "Dulche De Leche" by merchant gourmet, available at decerning supermarkets,otherwise you will have to boil a tin of condensed milk for a couple of hours!!!
You could make a milk jelly with the carnation milk, half the quantity of water and half carnation milk to instructions on jelly packet, i whip the carnation till quite aerated, and then fold in to cool jelly liquid, dont do it when the jelly is till hot, i love it!!