To surprise, crack and beat an egg into (7)
I believe the answer is:
stagger
'to surprise' is the definition.
(I've seen this before)
'crack and beat an egg into' is the wordplay.
I cannot quite see how this works, but
'an' could be 'a' and 'a' is found in the answer.
an anagram of 'egg' is 'gge' which is within the answer.
The remaining letters 'str' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stagger that I've seen before include "Walk as if about to fall" , "Lurch; astound" , "Reel - astound" , "Reel about; shock" , "Reel, walk unsteadily" .)