Another idea, though not a specific recipe, would be burrito bowls - rice, beans, sautéed peppers/onions/ tomatoes, cheese. I have an anti-sandwich teen and this is what he takes for lunch (with chicken) about half the time.
Or chili? We liked the black bean chili in the latest Smitten Kitchen cookbook, and it was super easy and (IIRC) worked just fine without chorizo. She has a recipe for 3-bean chili that looks similar, just use vegetable broth instead of the beer.
Or fried rice, maybe with edamame or tofu added for protein?
the tomatoes have been pressure canned inside these tins already - while I agree that the cans or their coatings may deteriorate over time, it seems to me that the surface must be able to withstand the amount of heat in a domestic pressure cooker or steamer set up.
I don’t have a recipe - but we used to make this for years. Steam some couscous in broth and a bit of evoo. Then fluff it and stir in currants, garbanzos, scallions, some rice wine or white vine vinegar and a bit of cranberry juice. The mix ins and frankly the dressing can be whatever flavors they enjoy, but the canvas is just a couscous-garbanzo cold salad.
I would think the school is keeping diets Dairy and Pareve, which would mean dairy, eggs and fish are all okay. (@Sasha , I realize you know this about Dairy and Pareve- I meant to respond to the OP! Some people do not realize Dairy includes eggs when it comes to the dietary laws)
I can’t imagine expecting a child to eat legumes every day, without dairy or egg alternatives.
I’m sure the kid will also see what other children have in their lunches each day.
Wow! So many more great ideas. And I am apologizing in advance if I misspell any of your Hungry Onion names; I need coffee.
Nigella—The bean recipe with gruyere looks great. I LOVE gruyere.
The toddler in question LOVES hummus. She’ll either gobble down salmon or nibble at it depending on the day. She also loves Moong Dal, rice and bean balls, edamame. All of these occasionally appear in her lunches
Unfortunately, she HAS looked at the other kids’ lunches which led her into a period of petty larceny! She stole other kids’ pouches! My daughter had tried to avoid pouches because anything she makes herself is so much better, but capitulated and is now sending occasional pouches (of the nutritious variety) because she does not want to encourage the toddler in pursuing a life of crime.
The beans braised in milk also look terrific.
Thanks, tcamp and Truman for giving a thumbs up on the Pizza Beans.
RE eggs—The toddler has entered a period of egg hatred. We keep offering and hoping she’s soon eat them again.
Re nuts–There are no nut allergies in her classroom, so nuts and peanut butter have been included in her lunches.
Love the link to the Mama Maven Blog.
HUGE thanks to all of you for your great suggestions.
Reminds me of when my younger nephew “confided” in me that he regularly traded his (chosen) snack of organic berries or similar for a kid size bag of chips of pretzels because his friends loved the berries and were always asking him for some… and of course he could just come home and eat them later
I think the only thing that upset both my SIL (of course I had to tell her, also in confidence) and me was that we were spending ridiculous amounts of money on said organic berries instead of a bulk pack of snack size pretzel bags
Most vegans I knew in high school (vegans by choice) subsisted on potatoes, not too many legumes.
Of course, it varies, depending on where you live, what foods are common in your community, what foods your family is familiar with, how broad your palate is, etc.
My 2 closest friends who keep Kosher. One basically is a carnivore who can’t stand hummus, will tolerate falafel, makes excellent Parve oatmeal chip cookies with margarine. His wife loves vegetables and legumes. She loves trying new things and ends up cooking enough things to satisfy him and their 3 kids. Occasionally she makes things she likes, as well.
Oh man, that would make me crazy—expensive organic berries, lovingly selected and carefully washed—traded away for a bag of junky food!!!
I always cringe a little when I see what portion of her lunch the toddler did not eat (and yes, she does not eat all of it every day because she’s a toddler) because I know how much time and care and $$ went into that lovely lunch.
Oh man, the capricious toddler. Such a challenge. I’m surprised that no one has come up with a refillable toddler approved pouch that savvy parents can refill with healthy options.
because his friends loved the berries and were always asking him for some… and of course he could just come home and eat them later 
