I've not eaten one of these things in a long, long time. So this seemed like an ideal time to recreate the experience, and share it with my dear readers.
I used normal Sainsbury's burgers from the fresh meat section... I doubt the ones Grubbs used were any better. I only had smooth peanut butter, but I improvised and added some chopped peanuts to make it crunchy. For the chilli sauce, I found two likely candidates in the fridge - some Chinese chili oil, and something labelled "Shu Han's sizzling shit-hot sambal". Sambal is actually and Indonesian / Malaysian chilli condiment, so it seemed perfect. I decided to use both the sambal and the Chinese chili oil.
I fried the burger on a high heat until charred, and mixed the ingredients for the "sauce" together in a bowl. It was very thick at first, so I added a little vegetable oil and some soy sauce.
Finally I assembled the burger.
It tasted amazing. Actually, a hell of a lot better than the Grubbs burger, if my memory serves me correctly. Thanks mainly, I'm sure, to Shu Han's sizzling shizzle (I believe this person is responsible for this awesome substance : http://mummyicancook.blogspot.co.uk/).