Ascertain amount of cooked veal before you, we hear, prepared tea (8)
I believe the answer is:
evaluate
'ascertain amount' is the definition.
'evaluate' can be an answer for 'ascertain' (thesaurus). I'm not sure about the 'amount' bit.
'cooked veal before you we hear prepared tea' is the wordplay.
'cooked' indicates an anagram (letters cooked into a new form).
'before' says to put letters next to each other.
'we hear' shows a homophone (sound like).
'prepared' indicates anagramming the letters.
'you' sounds like 'u'.
'veal' is an anagram of 'eval'.
'tea' with letters rearranged gives 'ate'.
'eval'+'u'+'ate'='EVALUATE'
'of' is the link.
Can you help me to learn more?
(Other definitions for evaluate that I've seen before include "Make an assessment of, determine worth" , "Make an assessment of, measure" , "'Assess, appraise (8)'" , "Judge the worth of something" , "Reckon worth of" .)