Dry fry the oatmeal over a moderate heat for about 5 minutes, shaking the pan, to toast the oatmeal.
Whip the cream together with the icing sugar and vanilla extract.
In a saucepan stir the granulated sugar and water together over moderate heat until all the sugar granules have dissolved completely. Only then let the syrup boil, and boil for 2 minutes, boiling fast. Stir the dryfried pinhead oatmeal into the syrup and scrape this onto a baking parchment lined baking tray – it will become hard and crystalline. When cold, bash with a rolling pin into crumbs.
When the crisp sugar-coated crumbs are cold, fold them into the vanilla flavoured whipped cream, and freeze this mixture in a solid polythene container with a lid. Bring the ice cream from the freezer just as you sit down to eat your main course. It should then be easy to spoon into a serving bowl when you’re ready to eat it.