Cake perhaps or jam (5)

I believe the answer is:

wedge

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'jam' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for wedge that I've seen before include "Jam" , "Tapering piece" , "Golf club, V-shape" , "A golf club; divisive idea" , "Tapered block" .)

I've seen this clue in The Globe and Mail.

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