Alfresco meal: be eating rotten EU crab? (8)
I believe the answer is:
barbecue
'alfresco meal' is the definition.
(I've seen this before)
'be eating rotten eu crab?' is the wordplay.
'eating' indicates putting letters inside.
'rotten' indicates an anagram.
'eu'+'crab'='eucrab'
'eucrab' with letters rearranged gives 'arbecu'.
'be' placed around 'arbecu' is 'BARBECUE'.
(Other definitions for barbecue that I've seen before include "Outdoor eating occasion" , "Cuba beer for outdoor meat meal" , "Cuba beer (anag.)" , "A picnic with grilled meats" , "Grill over an open fire" .)