Sauce alas knocked over contains salt (5)
I believe the answer is:
salsa
'sauce' is the definition.
(I know that sauce can be written as salsa)
'alas knocked over contains salt' is the wordplay.
'knocked over' says the letters should be written in reverse.
'contains' indicates putting letters inside.
'salt' becomes 's' (this could be a standard abbreviation which I don't know about).
'alas' reversed gives 'sala'.
'sala' enclosing 's' is 'SALSA'.
Can you help me to learn more?
(Other definitions for salsa that I've seen before include "hot stuff" , "The Latin-American sound" , "Dance or a dip?" , "that's rather spicy!" , "Spicy 7" .)