I forgot to mention yesterday that I also make oatmeal for Lexi. I actually didn't even think about making it for her when she first started eating solid food. Its pretty much the same as cooking/grinding rice. You put however much you want (I use Bob's Red Mill Extra Thick Rolled Oats)
Grind it up in the food processor, save the ground up oatmeal that you don't want to use in a container, and cook as much as you want to use at the moment or the next few days.
** Remember to keep stirring when you are cooking it, I would again use 1/4 cup of ground oatmeal and 1/2 cup of water first and add water if needed. DO NOT cook with breastmilk or formula. Add the milk in when serving.