Oven provides breakfast bread without topping (4)
I believe the answer is:
oast
'oven' is the definition.
(type of kiln)
'breakfast bread without topping' is the wordplay.
'breakfast bread' becomes 'toast' (I've seen this in another clue).
'without topping' means to remove the first letter (the top letter is removed).
'toast' with its initial letter taken off is 'OAST'.
'provides' is the link.
(Other definitions for oast that I've seen before include "Hop-kiln" , "Drying house" , "Cooker" , "Hop drying kiln" , "Kiln for drying hops or malt" .)