Spread the oatmeal on a baking sheet and toast lightly in a oven (120°C, 225°F, gas mark ¼) for 20 minutes.
Boil the milk in a pan, sprinkle in the oatmeal, stirring continuously over low heat for 10 minutes. Press through a sieve or purée in a blender, adding a tablespoon or so of milk if needed, to make a thick cream. Return to the rinsed-out pan.
Beat the egg yolks until fluf