Cinnamon Sugar Pillow Cookies

In a mixing bowl, combine first five ingredients, and stir well. Stir in the oil, milk, and vanilla to form a cookie dough. Only add extra milk if it's still too dry after a full minute of stirring. (I've never had to add more than the 1 1/2 tbsp milk.) Smush into a giant ball with your hands, or transfer dough to a plastic bag and smush into a ball once the dough is inside the bag. Now roll into balls. Break balls in half, flatten each half a bit and add a little filling to one half, then place the other half on top and re-roll. Chill 30 minutes or up to a day. Preheat oven to 325 F. Roll balls in cinnamon sugar, place on a baking tray, and bake on the center rack 11 minutes. They'll look underdone when you take them out, so let them cool about 10 minutes on the baking tray and they will firm up as they cool.