* The amount of oat flour you need will depend on whether you're using store-bought or homemade. Store-bought tends to be finer and will soak up more moisture, whereas homemade is a bit coarser and absorbs less moisture. If you're using store-bought, use less flour (1 cup to 1 ¼ cups), if you're using homemade, use more flour (1 ¼ cups to 1 ½ cups).