Preheat oven to 450 degrees.
Lay flat, cut sides of the potatoes on a well-oiled baking sheet. Potatoes should not overlap.
Lightly brush or mist the potatoes with olive oil. Then sprinkle with thyme, salt and pepper to taste. I like to sprinkle just the sweet potatoes very lightly with cinnamon sugar.
Roast for 20 minutes, then check for doneness. If the sharp end of a knife does not easily pierce the potatoes, cook in 5-minute increments until potatoes are just tender. Before returning to the oven, however, peek at the bottoms of the potatoes to see if they are nicely browned. If so, flip before cooking further. This will ensure the side touching the baking sheet does not burn as the potatoes continue to cook through.
