If she will eat dairy products and eggs, serve eggs in any form (scrambled, hard-boiled, egg salad, etc), and not just for beakfast.
I'd keep some canned soup on hand, such as chowder, cream of celery, cheddar cheese, etc. but check that they don't have chicken or beef stock in them.
You can make a quick cheap tomato soup with tomato paste. Its in the Tightwad Gazette books by Amy Dacyzyn. You take one can of tomato paste and put in saucepan. Add 3 or 4 (I forget) cans of water or milk. Mix well and heat. You may need to use a whisk of egg-beater to get this blended well.
Or frozen veggies would cook up into a nice soup.
Too bad she doesn't like beans. Has she tried lentils? Lentil soup would be good.
Canned tuna for tuna salad or casserole.
Pancakes and french toast. Potato pancakes. Oatmeal or other hot cereal. Peanut butter. I seem to recall making a peanut soup once but don't remember where I got the recipe. It was good though.
If she comes over on the spur of the moment, why not take her shopping with you?
Have fun!
K. Z.