Cheese sauce for pasta, califlower cheese or a kind of potato gratin.
Porridge bites. Not much milk but makes finger food.
Scrambled egg, fritatta or omelette
Bread and Butter pudding.
Flap jacks use milk don't they?
If you would give her jelly you can make a kind of blancmange with jelly cubes and milk. Not sure about the sugar/sweeteners though.
Anything you use milk in really.
Are you still pumping? If so you could freeze what you pump and use the freezer stash if she takes a bottle or cup so that you get longer to use it up (6m from when you freeze it).
Have you considered Eats on Feets who connect local mamas requiring breast milk for their babies with ladies like yourself who wish to donate?
http://www.eatsonfeets.org/