Preheat your oven to 400°F.
Peel the sweet potato and cut it into half-inch cubes.
Toss the sweet potato cubes on a large baking sheet with one tablespoon of olive oil, half the salt, and half the pepper.
Roast the sweet potatoes for 15 minutes.
While the potatoes roast, mince the garlic and fresh rosemary.
In a small bowl, whisk together the melted ghee, minced garlic, rosemary, and the juice from the lemon.
Trim the woody ends off the asparagus and toss the spears with the remaining half tablespoon of olive oil.
Remove the baking sheet from the oven and move the potatoes to one side.
Place the chicken breast and asparagus on the other side of the sheet, then brush the lemon-herb ghee mixture generously over the chicken.
Season the chicken and asparagus with the remaining salt and pepper.
Return the sheet to the oven and roast for 18 to 20 minutes until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for 5 minutes before slicing and serving alongside the roasted vegetables.