Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Wash and peel the sweet potato, then cut it into 1-inch cubes. Halve the Brussels sprouts and break the broccoli into bite-sized florets.
Place the vegetables on the baking sheet, drizzle with the extra virgin olive oil, and sprinkle with half of the sea salt and black pepper. Toss well to coat.
Roast the vegetables in the oven for 20-25 minutes, tossing halfway through, until the sweet potatoes are tender and the edges of the broccoli are crispy and charred.
While the vegetables roast, pat the chicken breast dry with a paper towel. Season both sides with the remaining salt, pepper, garlic powder, and dried thyme.
Heat the ghee in a large skillet over medium-high heat. Once hot, add the chicken breast and sear for 6-7 minutes per side, or until the internal temperature reaches 165°F (74°C) and the exterior is golden brown.
Remove the chicken from the pan and let it rest for 5 minutes before slicing.
Plate the chicken alongside the roasted vegetables and drizzle the fresh lemon juice over the chicken to brighten the flavors before serving.