Stink Soup by Jill Esbaum, illustrated by Roger Roth

From chapters.ca:
Annabelle and her little brother, Willie, are spending the week at Granny's. Annabelle, who has promised to keep her brother out of trouble, can't decide which is worse: being responsible for Willie, or helping Granny prepare tomatoes - which Annabelle hates - for home canning. Willie escapes his sister's surveillance to lasso chickens and torment the goat. Annabelle, when not searching for her brother, must squish hot tomatoes for juice - and find ways to avoid tasting the finished product. But the offending fruit ends up being of unexpected benefit as Willie's devilishness reaches an all- time high.