I've been going mad for the porridge lately.
I've not seen a specific recipe other that add pysllium husks to shake, more or less than a tbsp depending on how thick you want it.
I've tried porridge with almost all of my fav sweet shakes. It don't work with the cappuccino but is gr8 with the butterscotch, banana, toffee walnut and my last pack of orange winter spice porridge went down a treat. It's also really filling and allows you to linger on your 'meal' a bit longer.
I make mine by adding the 1 tbsp husks, shake powder, a couple of sweeteners to 350 mls hot water and whizz the lot together for 15-20 seconds. It tends to get thicker and gloopier the longer you whizz it though.