Edge of tart topping, say, lifted (6)
I believe the answer is:
flange
'edge' is the definition.
(I have seen 'Flat edge' mean 'flange' so perhaps 'edge' could also mean 'flange')
'tart topping say lifted' is the wordplay.
'tart' becomes 'flan' (I've seen this before).
'topping' is a charade indicator (letters next to each other).
'say' becomes 'eg'.
'lifted' says the letters should be written in reverse (going up in down clue).
'eg' in reverse letter order is 'ge'.
'flan'+'ge'='FLANGE'
'of' acts as a link.
(Other definitions for flange that I've seen before include "Projection used for attaching another object" , "Rim (on wheel)" , "wider opening" , "Flat outer face of rolled-steel joist" , "Projecting (steel) collar" .)