Here are two recipes I found, the first is pretty genera, the second more specific. I'm sure JA'ns use sweetened condensed milk instead of the evaporated mik.

Let me know if you try these or others. I'm a big porridge fan.

Peanut porridge

put a pot on fire make it boil. then blend raw red peaunuts and some water untill smooth. add a little oats to thicken peaunut mixure. then add mixure to boiling water. keep on stirring then simmer on low heat for about 10-15 minutes. keep checking and stirring. when cooked. turn off fire.
then sweeten add vanilla essence,condensed milk,little sugar,alittle nutmeg some cinnamon. and then you good to go

Peanut Porridge
½ cup raw peanut
1 cup oatmeal
1 tbsp. Flour
1 tbsp Cormmeal
Sweetened Condensed Milk
Evaporated Milk
A pinch of nutmeg
3 drops of Vanilla Flavoring
½ tsp Salt
Method:
Put the peanuts into an electric blender and blend the peanut until it is almost smooth. Remove the peanut from the blender and put it in a bowl.
Put the oatmeal into the blender, blend until the oatmeal becomes a powder. Combine the oatmeal, peanut, flour, and cornmeal into a pan. Add enough water to the mixture to make a liquid paste. Remember the flour and the oatmeal will give the porridge enough body to thicken it.
Bring water to boil in a pot, and then slowly pour the liquid paste into the boiling water. Add the salt to the pot. Keep stirring the pot, for ten minutes, to make sure that the flour does not get lumpy. Turn the fire to medium and place the pot cover onto the pot, slightly cocked to one side to allow the steam to escape; this prevents the porridge from boiling over.
Wait ten minutes and then stir the porridge again. Turn the fire down to low. Add vanilla flavoring and nutmeg. Add evaporated milk, and sweetened condensed milk to taste. Stir the porridge some more and then turn off the fire allow the porridge to cool and then pour into a bowl. Serve with bread, or just by itself.