Preheat oven to 350°F.
Mix the dry ingredients together.
Cream sugars and butter together. Blend in egg. Blend in vanilla. Mix in the dry ingredients, 1/3 at a time. Mix in the chocolate chips.
Make into balls and put on a sheet of parchment paper, on a cookie sheet. Leave plenty of space between cookies, these cookies really spread out.
Bake until done, about 12 minutes.
After taking out of the oven, let them sit on the cookie sheet for a few minutes. Then use a spatula to move them to a plate to cool.
They have less integrity when hot than most chocolate chip cookies, so they have to cool slightly on the tray or they'll break when you try to move them. Once they're cooled, they're fine.
I'm not kidding about them spreading out. I often put just six of them on a large cookie sheet.
Of all the cookies I make, this one seems to be my dad's favorite. The oat flour gives it a wonderful flavor.
You can play around a lot with the amount and type of oatmeal you add. I go between one and two ounces, and between regular (which I always have on hand), quick-cooking, and instant. Sometimes I'll mix them, too, an ounce of regular and an ounce of quick-cooking.