Sprinkle a baking board with medium oatmeal. Mix ingredients together and form into a ball. Place this onto a baking board that has been sprinkled with a little medium oatmeal and roll out the mixture into a round that is about 1/4" thick.
Cut into 4 triangles. Work quickly, since the mixture becomes difficult to work with if it becomes cold. (It will break and crack.)
Put the oatcakes on a hot griddle and bake on one side only. Once the edges curl, they are cooked and now must be placed on a rack or a tea towel and allowed to dry off in a warm room (or in the oven on a rack).
This is a traditional Scottish recipe, and is normally eaten with cheese, butter, or (non-traditionally, by Anna's son) hummus.
In the recent past oatcake manufacturers have added extra ingredients to their oatcakes to extend the range available in shops. These include mixed herbs, ground black pepper or even cheese. Once you have tried plain oatcakes why not try experimenting with the ingredients.