Tea, say, originally blended by Dame Edna (8)
I believe the answer is:
beverage
'tea say' is the definition.
(tea is a kind of beverage)
'by dame edna' is the wordplay.
'by' means one lot of letters go next to another.
'dame' becomes 'everage' (I've seen this before).
'edna' becomes 'b' (I can't justify this - if you can you should give a lot more credence to this answer).
'everage' after 'b' is 'BEVERAGE'.
'originally blended' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for beverage that I've seen before include "Non-alcoholic drink" , "Liquid for drinking" , "such as a Frappuccino" , "Prepared drink" , "Tea, say" .)