01 - Preheat oven to 425°F and line a baking sheet with parchment paper or lightly grease.
02 - Place baby potatoes in a large pot, cover with cold water, add a pinch of salt, bring to a boil, then simmer for 15 to 20 minutes until fork-tender. Drain and let cool for 3 minutes.
03 - Arrange potatoes on 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 with olive oil and sprinkle with garlic powder, smoked paprika, sea salt, and black pepper. Toss gently for even coating.
05 - Roast for 20 to 25 minutes, turning potatoes halfway through, until edges are crispy and golden.
06 - Remove potatoes from oven, sprinkle evenly with shredded cheddar cheese and green onions, then return to oven for 3 to 5 minutes until cheese is melted and bubbly.
07 - Transfer potatoes to a serving platter and garnish with chopped fresh parsley if desired. Serve hot.