Boil: First, place potatoes in a pot and cover with salted water. Boil for 15-20 minutes until tender. Drain and let steam dry for 5 minutes.
Preheat: Preheat oven to 425°F (220°C). Grease a large baking sheet with oil.
Smash: Place potatoes on the baking sheet. Use the bottom of a glass to gently press each potato flat until it is about 1/2 inch thick.
Season: Drizzle the smashed potatoes generously with olive oil. Sprinkle with salt, pepper, garlic powder, and dried thyme.
Roast: Bake for 25-30 minutes until the edges are deep golden brown and crispy. (Optional: Sprinkle parmesan on top for the last 5 minutes).
Serve: Garnish with fresh parsley and serve hot.