Bag containing initial slice of rich cake (5)
I believe the answer is:
torte
'rich cake' is the definition.
(I've seen this before)
'bag containing initial slice' is the wordplay.
'bag' becomes 'tote' (tote is a kind of bag).
'containing' means one lot of letters goes inside another.
'initial slice' becomes 'r' (I can't explain this - if you can you should believe this answer much more).
'tote' going around 'r' is 'TORTE'.
'of' is the link.
Can you help me to learn more?
(Other definitions for torte that I've seen before include "Rich food" , "Sweet cake or tart" , "1d [PASTRY]" , "(Austrian) cake with cream and fruit or nuts" , "Sweet cake (from Ger.)" .)