Some hot concoction to start with that's tasty (9)
I believe the answer is:
toothsome
'tasty' is the definition.
(thesaurus)
'some hot concoction to start with that's' is the wordplay.
'concoction' indicates an anagram.
'to start' means one lot of letters go next to another.
'with' is a charade indicator (letters next to each other).
'that' becomes 'to' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'hot' with letters rearranged gives 'oth'.
'some' after 'oth' is 'othsome'.
'othsome' put after 'to' is 'TOOTHSOME'.
Can you help me to learn more?
(Other definitions for toothsome that I've seen before include "It's just like a T-Rex" , "Inviting" , "attractive" , "Pleasing" , "Temptingly tasty" .)