Putting vessel inside oven like this is a bloomer (10)
I believe the answer is:
agapanthus
'a bloomer' is the definition.
(I've seen this before)
'putting vessel inside oven like this' is the wordplay.
'putting vessel' becomes 'pan' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inside' indicates putting letters inside.
'oven' becomes 'aga' (type of large oven).
'like this' becomes 'thus' (I've seen this before).
'aga'+'thus'='agathus'
'pan' going within 'agathus' is 'AGAPANTHUS'.
'is' is the link.
Can you help me to learn more?
(Other definitions for agapanthus that I've seen before include "Bloomer" , "flower" , "Southern African plant of the lily family -- haunts a gap (anag)" , "garden plant" , "Flowers" .)