The bottle and tart, leave inside (6)
I believe the answer is:
flagon
'the bottle' is the definition.
(thesaurus)
'tart leave inside' is the wordplay.
'tart' becomes 'flan' (I've seen this before).
'leave' becomes 'go'.
'inside' is an insertion indicator.
'flan' enclosing 'go' is 'FLAGON'.
'and' acts as a link.
(Other definitions for flagon that I've seen before include "Large vessel for beverages" , "Wine jug" , "Large wine-bottle, jug" , "Large vessel with a handle and spout" , "Large rounded bottle for cider or wine" .)