Preheat the oven to 425 degrees Fahrenheit.
Wash and scrub sweet potatoes, then dry with paper towels.
Cut potatoes into ⅓ - ½-inch thick slices and place in a mixing bowl.
Add 3 tablespoons olive oil, salt, garlic powder, ground cumin and smoked paprika.
Mix well until each potato slice is coated. Using your hands is the easiest way.
Place oiled and seasoned sweet potato slices on a large baking sheet in one even layer. The slices should not touch each other, if possible.
Place in the preheated oven and bake for 30-35 mins. Potatoes should be fork tender and lightly carmelized on top.
Transfer to a platter or a large plate and serve immediately. Garnish with fresh thyme or parsley leaves, if desired.