Meals cooked in – wow! – sweet wine (7)
I believe the answer is:
malmsey
'sweet wine' is the definition.
(I've seen this before)
'meals cooked in wow' is the wordplay.
'cooked' indicates an anagram (letters cooked into a new form).
'in' means one lot of letters goes inside another.
'wow' becomes 'my' (both can be expressions of surprise).
'meals' with letters rearranged gives 'almse'.
'almse' put inside 'my' is 'MALMSEY'.
(Other definitions for malmsey that I've seen before include "Fortified Madeira wine" , "Sweet Madeira wine" .)