01 - Preheat oven to 425°F. Line a baking sheet with parchment paper or lightly grease the surface.
02 - Place potatoes in a large pot and cover with cold water. Add a pinch of salt, bring to a boil, and simmer for 15 to 20 minutes until fork-tender. Drain and cool for 3 minutes.
03 - Transfer potatoes to the prepared baking sheet. Gently smash each potato to approximately 1/2-inch thickness using a flat-bottomed glass or potato masher.
04 - Drizzle olive oil over smashed potatoes. Sprinkle evenly with garlic powder, smoked paprika, sea salt, and black pepper. Toss gently to coat.
05 - Roast in the oven for 20 to 25 minutes, turning the potatoes once halfway through, until edges become golden and crisp.
06 - Remove baking sheet from oven. Top potatoes evenly with shredded cheddar cheese and sliced green onions. Return to oven for 3 to 5 minutes until cheese is melted and bubbly.
07 - Sprinkle potatoes with chopped fresh parsley, if desired. Serve immediately while hot.