Preheat your oven to 450°F (230°C) and place a baking sheet inside to heat.
Bring a pot of water to a boil and cook the mini potatoes for 12 minutes. Drain and rinse under cold water.
Once slightly cooled, remove the skins using a small knife and spoon.
Transfer potatoes to a bowl, sprinkle with salt, and toss. Add cornstarch and coat evenly.
Carefully remove the hot baking sheet, add your chosen fat, and let it melt.
Add the potatoes and toss to coat well.
Roast for 35–40 minutes, shaking the pan every 10 minutes until golden and crispy.
Mix all garlic mayo ingredients in a small bowl.
Serve crispy mini potato bites hot, topped with parmesan and green onions, alongside the dip.