Preheat the oven to 400 F.
Cut the potatoes in half or quarters, depending on their size.
In a medium saucepan over medium heat, combine the olive oil, butter and garlic, and bring to a simmer. Reduce the heat to low, and cook 1-2 minutes or until the garlic just starts to brown.
Place the garlic butter, potatoes, salt and pepper in a large bowl, and toss until every potato is coated.
Transfer the potatoes to a baking sheet lined with aluminum foil.
Roast for 45 minutes to 1 hour, rotating the pan and shaking/flipping the potatoes twice to ensure even roasting.
Remove from the oven and sprinkle with parsley. Transfer to a serving dish.