I used to be a nanny, and when the twins were 5, 6, and 7, I got them each one of Barbara Beery's cookbooks. I'd let each of them pick out a recipe in their cookbook (and each of them got a different cookbook each year, so by the end we had 6 of them), and we'd go shopping for the ingredients, then make the items. Eight might be a little old for those cookbooks, but something like this Whimsical Treats series might have a fun theme for her without going the character route.