I keep a plastic container of rolled oats in the cupboard mixed in equal parts with oat bran. Four scoops (about 50 grammes) is thrown into a saucepan and then I add the SECRET INGREDIENT: a chopped-up small banana which adds sweetness and flavour. Perhaps a bit of oat milk can be added to make it creamier. Don't forget to stir.
Boiled for about 15 minutes, the resulting mush, once cooled down, is quite delicious. Runs to about 1200 kJ without the oat milk.