Cook the Potatoes - In a large pot, bring the water to a boil over medium-high heat. Add 1 teaspoon salt, and stir to dissolve. Scrub and wash the potatoes, then add them to the pot. Cook until fork-tender, about 15 to 20 minutes.
Dry the Potatoes - Drain the potatoes in a colander, and let them sit and dry for 5 minutes. If needed, dry them with a paper towel to remove any moisture.
Heat the Oven - Set the oven rack to the middle position and the temperature to 400ºF (200ºC).
Smash the Potatoes - Transfer the potatoes to a large rimmed baking sheet. Drizzle with 2 tablespoons olive oil, and spread to coat. Use a potato masher, the bottom of a measuring cup, or a large fork to gently smash the potatoes. Keep them in one piece, about ½ inch thick.
Season - Evenly drizzle the potatoes with 2 tablespoons of olive oil. In a small bowl, combine 1 teaspoon of kosher salt, garlic powder, onion powder, and black pepper. Sprinkle on top of each potato.
Bake - Bake until the surface is golden brown and crispy, about 45 to 55 minutes. Cool on the baking sheet for 5 minutes before serving to make them crunchier.
To Serve - Garnish with parsley and serve while still hot and crispy.
Notes
Potato Size: Select potatoes about 1 1/2 to 2 inches in size.
Storing: Refrigerate in an airtight container for up to 1 week.
Reheating: Microwave on high setting in 30-second increments until hot. To make the potatoes crispy, place them on a foil-lined baking sheet and broil them on the lower-middle rack for a few minutes.