Sipping tea that's awfully tasty (10)
I believe the answer is:
appetising
'tasty' is the definition.
(I've seen this before)
'sipping tea that's awfully' is the wordplay.
'that's awfully' is an anagram indicator.
'sipping'+'tea'='sippingtea'
'sippingtea' with letters rearranged gives 'APPETISING'.
(Other definitions for appetising that I've seen before include "Mouth-watering" , "Tasty" .)