Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Trim the Brussels sprouts and peel the carrots, then cut them into bite-sized pieces.
Place the chicken breast, Brussels sprouts, and carrots on the baking sheet.
Melt the grass-fed butter and drizzle it over the chicken and vegetables.
Sprinkle the sea salt, black pepper, dried thyme, dried rosemary, and garlic powder evenly over everything.
Toss the vegetables to coat and ensure the chicken is well-seasoned on both sides.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are caramelized.
While the chicken rests, toast the sourdough bread and spread the cheese spread over it.
Slice the avocado and serve it alongside the roasted chicken, vegetables, and toast.