dizoz:
Well, I got a few more but I got stuck again. Here are a few hints for you.
20D is connected with an
obese mallard (work it out, google it & there he is).
14D has kind of been solved on this thread - he wrote 'Jerusalem: A Cookbook'.
3D Is a chap whose surname is (appropriately enough) a mixture which is used in sauces. Actually, there are two of them, snr & jr.
... and that's where I ran out of answers myself. Any other hints appreciated.
dizoz, take care & stay well.