Instructions
Preheat oven to 350°F.
Place the potatoes in a bowl. Add the butter, olive oil, garlic, salt and pepper. Stir well to combine.
Spread the potatoes on a sheet pan. Roast for 40 minutes until golden brown on the outside and soft on the inside, turning them over halfway through.
Meanwhile, put the dressing ingredients in a jar. Shake well to combine.
When the potatoes are cooked, transfer them to a bowl. Add the onion and fresh thyme, pour the dressing over the potatoes and toss. Serve hot.