Mandarins are usually sweeter if a frost hits them just before they ripen. I had a mandarin tree at my previous house. Yum!

And chestnuts! I treat myself to a small bag every year when the price is not too high. I boil them and smother them with butter and a little salt, and the nut is soft-textured with a mild flavour which is hard to describe.

If you get one that is rotten it smells - & probably tastes - foul, though. If it is rotten the inner nut is dark in colour.

Helen