Give the potatoes a quick scrub and cut them into small cubes (roughly 2x2cm - see photo or video).
Then throw them into a bowl, and use a spatula to make sure they get a good coating of oil. Sprinkle some salt over too.
Layer the cubes out on a baking tray, ideally with parchment paper and in they go for 25 mins. Halfway through give them a bit of mix with said spatula.
In the meantime peel and crush the pistachio (we found the easiest way was to put them in a bowl after shelling and use something sturdy and heavy like a thick glass or end of a rolling pin to crush them).
Wash and slice the spring onion into fine rings, then add them to the bowl.
Add the basil to the bowl too (cut first if using leaves). Add the maple syrup, mustard, olive oil and water. Stir well.
Fetch the potatoes from the oven, and serve them onto the plates.