Asparagus
Toasters can effectively cook plain old vegetables as well as plant-based burgers. One component that benefits from the even heating of the pop-up toaster is asparagus, a notoriously finicky stalk that is challenging to cook evenly and consistently due to the variation in thickness of the stalks to stems (via The Guardian).
Cooking in a toaster bag is essentially necessary because of their thinness, which makes it far too easy for them to fall through the slots. To make sure they all fit and that the points of the tops rest just below the toaster's rim, you might also need to cut the stalks, depending on their size. Cook on the highest setting twice, and you're done! You can quickly prepare asparagus that is ready to eat as well as a filling side dish by seasoning to taste and possibly cutting them into bite-sized pieces.