Whisk together groats, flakes, flour and water in a small saucepan.
Bring the porridge to a boil. Turn down the heat and let the porridge cook for 2-3 minutes while stirring in the pan.
Remove the pan from the heat and switch off the cooker.
Add fat and infant formula to the porridge.
Add if necessary, a little fruit puree to sweeten the taste.
Pour the porridge into a small bowl and check that it has the right eating temperature before giving it to the baby.