Creating The Best Crispy Roast Potatoes Ever is straightforward if you follow these easy steps:

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Prepare Potatoes: Peel and chop the potatoes into equal-sized chunks, about 1.5 inches in size. This ensures even cooking.
3. Parboil Potatoes: Place the potatoes in a large pot, cover with cold water, and add a pinch of salt. Bring to a boil and cook for 10 minutes until slightly soft.
4. Drain: Carefully drain the potatoes and let them sit in the colander for a few minutes to dry out.
5. Rough the Edges: Return the potatoes to the pot. With the lid on, shake the pot gently to roughen the edges of the potatoes, creating a greater surface area for crispiness.
6. Add Oil: In a large roasting pan, add the vegetable oil. Heat the pan in the oven for about 5 minutes until the oil shimmers.
7. Combine with Seasoning: Carefully add the roughened potatoes into the hot oil. Sprinkle with sea salt, black pepper, garlic powder, and rosemary, if using. Toss until evenly coated.
8. Roast: Spread the potatoes in a single layer. Roast in the preheated oven for 40-50 minutes, turning them halfway through to ensure even crisping.
9. Check for Crispiness: They should be golden brown and crispy on the outside while fluffy on the inside. Adjust your cooking time as needed based on your oven.
10. Garnish and Serve: Remove the potatoes from the oven and serve hot, garnished with lemon zest if desired.