I just watched the video that Goldfish directed me to. It was interesting but she didn't say how fast she was going at any point which was a little annoying.
I ended up using 250g roasted, unsalted cashews and an additional 50g of salted, roasted macadamias. Based on a non TMX recipe I simply put the nuts all in and processed on sp9 them continuously until they started to come together as a butter (24 seconds, as compared to the 13 minutes of the food processor recipe). I scraped down the side and processed again on sp9 for another 20 secs, scraped down again, and repeated for another 10 seconds.
The final product is tasty but still quite 'grainy' as the nuts started to go to butter before they were powdered. I just tested it out on a piece of toast and will offer it to the kids for breakfast in the morning (perhaps I will just give it to them rather than offer it...).
I wonder if I should have done the macadamias first as they are a tougher nut, or whether I just needed to whizz them on a lower speed for a longer time before trying to get it to combine at the higher speed? Can anyone offer any suggestions as to how to avoid this? I know DS10 will say that he only likes smooth peanut butter...
Also, at the higher speed the TMX was making a horrific noise that is still making my teeth hurt to think about it - think blackboards and finger nails... youch! I have never heard it make that noise on that speed before.