If you're having trouble figuring out appropriate substitutions, can you give me an idea of what the recipes are? Asparagus and peas are generally going to be easy to substitute. Tomatoes may be harder, but I might have suggestions. Beans likely could be omitted entirely.
I hear you, though. My sis is allergic to onions. Do you know how many recipes have onions? I've learned to substitute carrots, celery, or a combination of them in recipes I make for her.