British adore eating one at Trump's talk - in a grandiose fashion (8)
I believe the answer is:
bloviate
'trump's talk in a grandiose fashion' is the definition.
(to talk at length in the US, eg for Donald Trump)
'british adore eating one at' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'adore' becomes 'love' (I've seen this before).
'eating' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'i'+'at'='iat'
'love' enclosing 'iat' is 'loviate'.
'b'+'loviate'='BLOVIATE'
(Another definition for bloviate that I've seen is " Speak arrogantly to Americans".)