How do you make sure aubergine doesn't go bitter when cooking? Sometimes aubergine and courgette tastes fine when cooked as is, but other times they are so bitter that they're almost inedible. I've tried dry salting and leaving the slices in salt water beforehand for various lengths of time, but this is a mission and can often make them too salty. Also the outcome seems pretty random given that sometimes this isn't necessary. Is it to do with freshness?
Yes, it is to do with freshness - the fresher and younger the aubergine, the less bitter it will be. If you have an old aubergine, you could try peeling it, as the bitter compounds are concentrated just under the skin.