@laughoutlood,
The secret word consists of 5 letters. If I accept "appreciated" for 7a,(I was grateful for a very soft rice and date pudding (11 letters) the first two letters are 'AE'.
If Perth is correct,the first three letters are "AEP"
I have 'splitsecond' for 18a, (An instant dessert for boxer's assistant (5,6 letters) now giving me the first four letters as "AEPP"
Now the clue for 14d is 'Artist leaves caramel for desert animal (5 letters). I submit the answer here would be 'camel'.
This now gives me the following 5 letters: AEPPL. Obviously this is not a word, so we're wrong somewhere!