I'm planning to make Parkin from a british cookbook I have and it calls for 350g of medium oatmeal. Googling it leads me to believe that medium oatmeal is a coarse ground oat flour. Can I take steel-cut oats and grind them in my food processor to create something close to medium oatmeal? I'd rather not buy it over the internet, as I have rolled oats and steel-cut oats. Can either of these be transformed into medium oatmeal? TIA for any advice.