Hmm, I don't do a lot of cheesy casseroles since cheese and I don't get along these days, but there should be some options. I've made a sheperd's pie with a lot of vegetables and mashed sweet potatoes on top, I've made a bulgur red pepper casserole with feta. I've made stuffed pita sandwiches with red beans, corn and a little cheese. Stir fries aren't cheesy, but hey are a good super food non salad variety. For simple, I like to roast up a huge pan of veggies (carrots, diced sweet potato, tomatoes, beets, red onion, zucchini, broccoli and serve it over whole wheat couscous or quinoa).
I guess I do things a little differently, I find a recipe with super foods and then go to the store! There are literally millions of recipes on the internet.
Here's some info on flax seed: