To make oat flour, whiz instant or rolled oats in your blender until it reaches a flour-consistency. Mix 1 cup oat flour, cornstarch, baking soda, salt and spices together in a mixing bowl until well combined. Add remaining ingredients and stir until combined. Set batter aside to rest while oven heats to 350F. Grease a cookie sheet or line with parchment paper. Drop 14 spoonfuls of batter on to the cookie sheet and bake 10-15 minutes, or until cookies are firm to the touch.