What gives some gripes — tomato sauce (5)
I believe the answer is:
pesto
'sauce' is the definition.
(I know that pesto is a sauce)
'what gives some gripes tomato' is the wordplay.
'what gives some' says the answer is hidden in the clue (the answer is given by some letters in the clue).
'PESTO' is hidden within 'gripes tomato'.
(Other definitions for pesto that I've seen before include "sauce involving Basil" , "Ligurian food" , "Green sauce" , "Saucy work" , "Basic sauce" .)