01 - Preheat oven to 425°F. Line a baking sheet with parchment paper or lightly grease.
02 - In a large pot, cover potatoes with cold water and add a pinch of salt. Bring to a boil, then reduce heat and simmer for 15 to 20 minutes until fork-tender. Drain and let cool for 3 minutes.
03 - Transfer potatoes to the prepared baking sheet. Using a flat-bottomed glass or potato masher, gently press each potato to about 1/2 inch thickness.
04 - Drizzle smashed potatoes evenly with olive oil. Sprinkle with garlic powder, smoked paprika, sea salt, and black pepper. Toss gently to ensure even coating.
05 - Roast for 20 to 25 minutes, turning once halfway through, until edges are golden and crisp.
06 - Remove tray from oven. Top potatoes with shredded cheddar and green onions. Return to oven for 3 to 5 minutes until cheese is melted and bubbly.
07 - Garnish with chopped parsley, if desired. Serve hot.