Tofu is a plant protein. And a real versatile food item.
Tofu comes in 'soft', firm and those 'silken' brands that are in a box.
OH! and as for storing tofu... any uneaten tofu must be stored IN the fridge, AND IN WATER. Very important. If not the tofu won't last and will spoil. It MUST be stored/kept in water. Enough water to cover the top.
Here where I live, it is like a staple food.
One way to eat it is cold... plain, and just slice small cube pieces for her to eat with her fingers. That's what most kids do.
Or yes, you can make stir fry with it with veggies and oyster sauce and soy sauce... but make the tofu the last ingredient you add, otherwise it will break up during the tossing/stirring of the dish as you cook.(the seasonings are all to taste).
As far as tofu... it is eaten a lot in Japan and other Asian cultures. If you like Asian cuisine, one way to eat it is.... cold. Slice it up into about 1/2" cubes, and drizzle with sesame oil, soy sauce, and sesame seeds. Its real yummy. And then you can sprinkle chopped up scallions on top.
Some people like to slice it length wise, and put in in sandwiches too.
Tofu is great in that, it is good with sauces... and it takes on other flavors well, it can be eaten cold or hot.
Or, cut it into small cubes and make Miso Soup. Kids like miso soup... just get "miso" (which is a soy bean paste), add about 1/2 Cup to about 5-6 cups of water (the amount of water to miso is up to you and all according to individual taste), heat it up on the stove top, add some cubed tofu, and some people like to add an egg (an egg dropped into it and swished around with a spoon), and that's it! It's real good, and good for when you are sick too. It's a comfort soup.
My kids liked tofu as toddlers, but not anymore. I know with soy "milk" there are contraindications for it because there are naturally occurring estrogen in it... and basically, soy 'milk' is not a natural soy item that even Asians drink. It is mostly a Western contrivance. So.... but I don't know about Tofu.
I'm sure if you look up tofu recipes and/or Asian recipes with tofu, there are TONS of recipes.
Good luck and hope this helps,
Susan