Polenta is actually very easy to make, and it's fairly kid-friendly for a whole grain - especially when you serve it with some familiar flavors.
I have found that the easiest way to make it is in a double boiler - it takes longer than other methods, but it's pretty hands-off. If you don't have several hours at home when you can cook it (while doing other things), then make it at night or on the weekend, pour it in the pie pan, and refrigerate it until you're ready to top it and bake.
Polenta: (from A New Way to Cook by Sally Schneider)
1 cup polenta or yellow cornmeal, preferably coarsely ground
1 tsp kosher salt
4 cups cold water
To cook polenta in a double boiler: In the top of the double boiler, combine the polenta, salt, and water (or use a stainless steel bowl set over a saucepan of simmering water). Set over, not touching, simmering water, cover with a lid (or foil), and stir the polenta frequently during the first 20 minutes. After that, stir the polenta every 20 to 30 minutes for a total of 1 1/2 to 2 hours until the polenta is thick and has no trace of bitterness. (Replenish the simmering water as necessary.)
At this point, I've lately been stirring in some winter squash that I bake while the polenta is cooking - it doesn't add much flavor, maybe a bit of sweetness, but it does add some nutrients, and you hardly notice it.
Then I pour the mixture into a pie pan and smooth it out. You can cover and refrigerate it until you are ready to finish the dish.
There are a lot of options for polenta toppings. This one is particularly kid friendly - I'm just adding tomato sauce (either home-made or not, depending on what you have) and cheese. I often add pureed yams or carrots (or both) to jarred sauce - I make a puree and freeze it in an ice cube tray, and then put the cubes in a plastic bag. When I want to use them, I just heat them in the microwave and stir it in. You can also use canned pumpkin, or some of that baked squash, if you made some for the polenta.
This looks like a Pyrex commercial...
Bake it in the oven until the cheese melts - polenta works well with stronger cheese flavors: I'm using a very sharp cheddar here, but you could stir feta into the polenta before you put it in the pie pan, or you could top with Gorgonzola or whatever you think your kids would eat. If mild is the only thing that will pass your child's lips then go for it.
For members of the family that don't gag when their food is covered in "green bits", add flat leaf parsley and cracked pepper. Yummmm!
Of course, if you really don't feel like making polenta, you can buy pre-made polenta logs - I got one at Trader Joe's and sliced it up, just to see how it would compare. Here they are on a baking tray.
Here is the store-bought sauce with pureed carrot and yam. Sometimes I make my own sauce and freeze it in batches, but I've been way too lazy lately...
Aren't they cute?
Mmmmm, parsley. Did I tell you I have a thing for parsley?