Don’t know what I did wrong but my Macaroni Cheese ended up like scrambled eggs with macaroni. Are there different kinds of evaporated milk?
Nigella's recipe for Macaroni Cheese (from NIGELLA EXPRESS) avoids making a traditional bechamel cheese sauce. Instead it has a combination of eggs, cheese and evaporated milk to form a savoury custard. Evaporated milk is made by reducing the water content in milk, so evaporated milk is richer and slightly thicker than regular milk. It does not contain any sugar and should not be confused with sweetened, condensed milk.
However we suspect from the description that the evaporated milk was not the cause. If the eggs have scrambled then at some point they were exposed to high heat. This may have happened when the egg and milk mixture was added to the drained pasta. The pasta pan should be off the heat at this point and if it was still over a high flame then the mixture can scramble. You can also let the pasta cool very slightly before combining it with the egg and milk mixture. The oven is quite hot, but as the heat is indirect there is less risk of the mixture cooking too much. However if you are worried you can lower the oven heat slightly and check the dish regularly, until the macaroni cheese is piping hot all the way through and golden on top.