Cook the potatoes - Steam until very soft and smashable, about 25 minutes. While the potatoes are steaming, melt the butter and chop the parsley, chives, and scallions.
Preheat the oven and smash the potatoes - Preheat the oven to 400 ℉, convection roast setting. Gently smash each potato with a spatula. You want them to be about 1/2 thick.
Roast the smashed potatoes - Drizzle them with the melted butter, then spritz with olive oil. Sprinkle with salt and pepper, then roast for about 30 minutes, until they're brown and crispy.
Finish - garnish with chopped parsley and alliums (and anything else your heart desires) and serve.