Brandy very appealing initially, as cold unfortunately outside (8)
I believe the answer is:
Here is my best explanation:
'brandy' is the definition.
(Calvados is an example)
'very appealing initially as cold unfortunately outside' is the subsidiary indication.
'initially' says to take the initial letters.
'unfortunately' is an anagram indicator.
'outside' is an insertion indicator.
The initial letters of 'very appealing' is 'va'.
'ascold' anagrammed gives 'caldos'.
'va' going into 'caldos' is 'calvados'.
(Other definitions for calvados that I've seen before include "drink", "Drink", "Vocal ads (anag) - apple brandy", "Apple brandy", "A brandy", "Brandy distilled from apple cider", "Type of apple brandy" and "area near Caen".)