There are a few ways of going about cooking hot cereal with whole grains.
I decided to cook my cereal in a crock pot. If your crock pot doesn't run hot, you can probably just put the pot on low, and your cereal will be cooked in the morning. Mine runs hot, even on low, so after 3-4 hours, my cereal was finished. I just put it into glass storage containers and into the fridge once it cooled. The picture below is after it had been refrigerated overnight and I had scooped a portion out. I ended up with about 8 cups of cooked cereal.
This morning, I added a little water to 2/3 cup cooked cereal and microwaved mine to heat it up for about 1 minute. Perfect!
Another method is to cook the cereal in a covered casserole in your oven overnight. It can bake at about 150* to 200* overnight. Don't sleep in though, or you may have overcooked (hard) cereal!
From the old LDS Cannery Cookbook, there is a recipe for using 1 cup of whole wheat (or other grain), and adding 2 cups of boiling water to it in a thermos (with a little salt), and storing it overnight. I am sure this would be a bit on the chewy side!
Here is the recipe I used last night:
1/2 c. quinoa (Bob's Red Mill-prewashed)
1/2 c. hard red winter wheat
1/2 c. oat groats
1/2 c. pearl barley
quinoa top left, wheat top right, oat groats bottom left, pearl barley bottom right
I combined all of the grains in the crock pot with 4 1/2 cups of water and 1/2 tsp salt. I added another cup of water after about 3 1/2 hours of cooking on low. I think that erring on the side of extra water won't hurt at all. I unplugged the crock pot after about 4 1/2 hours, and it was perfectly cooked. You can use any combination of whole or cracked grains with this recipe, and even cut it in half if you have a smaller crock pot. The ratio is 1/2 c. grain to 1- 1 1/2 c. water.
I served my cereal with Greek yogurt and blueberries for breakfast. Delish!