Go Green.

Warm and healthy, lots of vegetables. Doing more chores around the house could also be a generous way of showing support, I do as much as I can at home to help my mom's stress. bumblehoneyb

Anything.....

Literally anything. Depression can be so draining that it's exhausting to do daily activities, like cooking dinner. Just simply supporting them in the way you are is bound to help. You sound like a great kid - I hope you're well and that your parents start feeling like themselves soon. staringoutinwonder

The Favorite. 

Think of the favorite meal your Mother made for you and make them that. Tell her why it's so special. I'm really sorry you're going through this, my own Mum suffers from bouts of depression too and it's very hard. I talk to her about special memories from my childhood and it seems to help.

EDIT: Woke up this morning to a bunch of replies and more gold than I know what to do with, thank you so much everyone but please, call your Mom instead and tell her how awesome she is. :) zerbey

Dear Mother...

I'm sure they would appreciate anything you cook them as long as you put time and effort into it :) Adams2799

Oh boy how I wish my parents acted like they cared more about something that comes from the heart instead of something expensive. Made my mom steak for dinner one Mother's Day, wasn't good enough she wanted to be taken out so her Mother's Day was ruined. Reddit

Classics...

Something they consider comfort food. It's different for everyone, but start with the classics. Chicken pot pie for instance. AudibleNod

The Thought that Counts....

Ok, so, I'm a parent and I struggle with depression and mental health problems, and honestly, I think even if i just knew my kid had asked this question and was trying to think about how to take care of me, it would mean the world to me. (Well, at the moment he's only 13 months old so I would also be pretty astonished, but you know what I mean.)

But I would also be a little bit worried, and I would want my kid to know that it's not their job to fix, or even help, my mental illness.

And I'd want to make sure that they were okay, and not taking on too many responsibilities that they weren't really old enough to cope with. So, since you already have a bunch of good suggestions and recipes in this thread, I'm going to just suggest that you make sure you're looking after yourself as well as your parents, and that you ask for help if you need it. Good luck with everything.

(Also, pasta. It's easy, it's good comfort food, most people like it, and you can vary the sauce/sides to include protein and veg.) Reddit

No Help. 

This post breaks my heart. I wish I had an answer for you, but the truth is we can't fix someone else's depression at any age.

Good on you for trying (that's what humans do). But if it doesn't work, don't blame your chicken soup. Depression is a bear. o_shrub

pasta... pasta.... 

I got this answer from a friend, Spaghetti. They tell me spaghetti tastes 100x better when your sad.

Haven't tested myself, but I trust them. Also they're probably reading this as well, so uhh.... Hi. NightsBane155

You can never forget spaghetti. I will make some for my parents :) legaladvicethrowawa9

Vitamins....

Anything with potassium. black beans are a great source of it (bananas really don't have THAT much) a B12 supplement and a multivitamin. Food wont solve depression but having the building blocks and the energy to work on yourself will go a long way. Plus the daily morning activity of taking your vitamins can be a tool to put yourself in a self care mindset. Ustinklikegg

Old Faves....

Old nostalgic homemade recipes would be a good bet. any way of getting to know their old favorites? NoopeNotTaken_

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