Sulphur smell beginning to escape 100 litres removed from Lake Victoria? (6,4)
I believe the answer is:
sponge cake
'litres removed from lake victoria?' is the definition.
I can't judge whether this definition defines the answer.
'sulphur smell beginning to escape 100' is the wordplay.
'sulphur' becomes 'S' (synonyms).
'smell' becomes 'pong' (pong can informally mean a smell).
'beginning to' suggests taking the first letters.
'c00' becomes 'cake' (I can't explain this - if you can you should give a lot more credence to this answer).
The first letter of 'escape' is 'e'.
's'+'pong'+'e'+'cake'='SPONGE-CAKE'
(Other definitions for sponge cake that I've seen before include "Victoria sandwich, say" , "Dessert" , "beggars might choose?" , "Victoria for instance" , "Light item of bakery" .)