In a stock pot, add water, kosher salt, the potatoes, and turn the heat medium, and bring to a boil. Boil potatoes until they are softened and easily pierced with a fork, about 18-22 minutes, then drain away water.
Spray your air fryer basket with a little oil, line air fryer trays with foil or parchment. Add the potatoes, being careful not to overcrowd each tray. Take the bottom of a glass and flatten the potatoes to smash them.
Preheat your air fryer to 400°F. Drizzle the potatoes with oil, then season generously with salt, reserving some for your garlic & herb topping that will go on later. Bake for 35 minutes, flipping halfway through to make sure every potato crisps up nicely.
While potatoes are cooking, mix together melted butter, parsley, thyme, rosemary, black pepper, red pepper flakes, garlic and parmesan. Toss to combine and set aside.
After the potatoes are crispy, distribute the garlic herb & butter topping over top of the crispy potatoes. Set the air fryer back to 400°F. Add the potatoes back to the air fryer for 3-6 minutes, keeping a close eye on the potatoes so the garlic doesn’t burn. Serve, and enjoy!
These will keep in a sealed container in the fridge for up to 5 days.