As can be seen in this picture, there is no way to make vegetable soup using carrots, onions, or potatoes. They aren’t even allowed in the broth. They aren’t wild vegetables either, as I am carrying them right now. This is problematic because it makes it more difficult to remove the -1 morale penalty with plain carrots by putting them to use. These all obviously are ingredients in vegetable soup, as can be seen in this recipe: http://www.delish.com/recipefinder/vegetable-noodle-soup-recipe-7908, so it would be a useful improvement to allow them in the recipes.
On another note, the vegetable pizza recipe is missing onions.