Here's some of my home made porridge I cannot eat oats so any porridge or gruel that I eat must use an alternative, rice flakes works well as does quinoa flakes you can also use coarse polenta ground rice gari (coarse tapioca) and it doesn't matter which you use you want around 35/50g to 350ml of liquid. With rice flakes I leave them to soak overnight. And I used coconut milk.
I added chia seeds sultanas which I add before I cook so they are nice and soft and I topped with sliced banana and raspberries.
I also really like a pudding especially in the winter so make many puddings with the same recipe and different grains and fruits...😊