Undivided cooking apple on right of oven (4-4)
I believe the answer is:
open-plan
'undivided' is the definition.
(I've seen this before)
'cooking apple on right of oven' is the wordplay.
'cooking' is an anagram indicator (letters cooked up into a new form).
'right of' indicates one should take the final letters (letter on the rightmost end of the word).
The final letter of 'oven' is 'n'.
'apple'+'on'='appleon'
'appleon' with letters rearranged gives 'openpla'.
'openpla'+'n'='OPEN-PLAN'
(Other definitions for open-plan that I've seen before include "Having no walls between areas" , "No pen pal in office lay-out without partitions" , "Offices without walls" , "(Of office) having few dividing walls" , "Office without walls" .)