Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Peel the sweet potato and carrots, then dice them into uniform 1-inch cubes to ensure they cook at the same rate.
Place the turkey breast in the center of the baking sheet and arrange the diced root vegetables around it in a single layer.
Drizzle the olive oil over the turkey and the vegetables, then sprinkle everything evenly with the dried rosemary, thyme, garlic powder, sea salt, and black pepper.
Toss the vegetables with tongs to coat them thoroughly in the oil and spices, and rub the herb mixture into the turkey breast.
Roast in the oven for 25 to 30 minutes, or until the turkey reaches an internal temperature of 165°F and the vegetables are tender and lightly browned.
Let the turkey rest for 5 minutes before slicing it into medallions, then serve immediately alongside the roasted vegetables.