Steam the potatoes in the instant pot for 7 minutes, manual/quick release. If you don't have an Instant Pot then parboil them till a fork goes through - not super soft.
Press the potatoes down with the back of a fork to "crack" them just a little - those beautiful bits will get lots of flavour
Heat the oil in a large wok, add the clove of garlic, stir fry 30 seconds.
Add 2 tbsp of butter, tip in the potatoes as soon as it melts.
Now put in 1 tsp of green chilli paste and a few pinches of salt and stir fry on high heat till most of the smashed edges are crispy and golden - 5 to 7 minutes
Taste for seasoning and see if you want to add the remaining green chillies and butter. Serve hot. These reheat well on the wok too.
If you don't have green chilli paste then simply grind 3-6 green chillies with a little water. You can also mince a few, but the taste will change a little.