'Noodle' does indeed have a plural form! In fact, your title should read 'A question regarding noodles'. 'Noodle' is a countable noun. 'A noodle' is a single strand. If you only had a noodle for lunch you would be very hungry indeed! 'Noodles' is the plural form. A bowl of noodles, for example. The sentence 'My favourite food is noodles' has nothing to do with whether this foodstuff is grammatically countable or not. It's to do with verb accordance. The verb has to agree with the subject immediately preceding it. In this case, the subject is 'My favourite food' (singular) so the verb following it is in the singular form 'is'. Another way of saying this is 'Noodles are my favourite food'. In this case, the subject is 'noodles' (plural) , so the verb following it is in the plural form 'are'. I'm not sure why you say that we normally say 'My favourite fruit are apples'. We don't. It sounds wrong because of the mismatch between 'fruit' and 'are'. We would normally say 'Apples are my favourite fruit' to avoid this awkwardness. And I've really no idea why you are confused by the sentence 'I love noodles. They are delicious'. It's a perfectly straightforward sentence. If you can say 'I love apples. They are delicious' , why can't you say the same about noodles?

thanks

Noodle: a narrow strip of unleavened egg dough that has been rolled thin and dried, boiled, and served alone or in soups, casseroles, etc.; a ribbon-shaped pasta. Seeing as 'noodle' is only one strip, the whole dish consists of many strips and should be referred to as 'noodles' HOWEVER, because you're only referring to ONE favourite food, the 'dish' as a whole is still singular. This is why you use 'is' instead of 'are'. If you have more than one favourite food, then you would use 'are': My favourite foods ARE noodles and boiled eggs. Referring to apples, 'your favourite fruit is apples' would be the correct way of saying it.