Crossword Genius

Mashed potato father had just like that (2,3,4,2,1,3)

Ross

I believe the answer is:

at the drop of a hat

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'just like that 234213' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'mashed potato father had' is the wordplay.
'mashed' indicates anagramming the letters.
'potato'+'father'+'had'='potatofatherhad'
'potatofatherhad' is an anagram of 'AT THE DROP OF A HAT'.

Can you help me to learn more?

(Other definitions for at the drop of a hat that I've seen before include "just like that" , "in no time at all" , "suddenly?" , "without delay" , "When a tile falls to the ground" .)

I've seen this clue in The Telegraph.
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