Parboil the Potatoes: Place the quartered potatoes in a large pot and cover with water. Season the water generously with salt. Bring to a boil over high heat. Once boiling, remove from heat and drain the potatoes. Set them aside to dry.

Preheat the Oil: While the potatoes are drying, preheat your oven to 400°F (200°C). Pour the olive oil into a rimmed baking sheet or baking dish, add the minced garlic, and place it in the oven for about 5 to 7 minutes to heat the oil.

Roast the Potatoes: Carefully remove the hot pan from the oven. Arrange the parboiled potatoes in a single layer on the pan, cut side down, ensuring they do not overlap. Roast in the oven for 30 to 35 minutes, or until the bottoms are golden brown and crispy.

Add the Onions: Remove the pan from the oven and flip the potatoes to the other cut side. Scatter the sliced onions over the potatoes. Return the pan to the oven and roast for an additional 25 to 30 minutes, stirring occasionally to prevent the onions from burning, until both the potatoes and onions are golden and crispy.

Season and Serve: Once roasted, remove the pan from the oven. Season the potatoes and onions with salt and freshly ground black pepper to taste. Transfer to a serving platter and garnish with chopped fresh chives, if desired. Serve warm and enjoy!