Preheat the oven to 425F convection (if you don’t have convection, preheat to 450F). Line a baking sheet with parchment paper.
Add carrots, apples, and cabbage to the baking sheet. Toss with 2 tablespoons oil, ½ teaspoon salt, and rosemary. Spread into an even layer.
Place the chicken on top (skin-side-up), drizzle with remaining 1 tablespoon olive oil, sprinkle the remaining 1 teaspoon salt all over, and then use your hands to rub all around to coat each piece.
Bake for 35 minutes, or until veggies are nicely charred/browned and chicken skin and golden and crispy. If the skin isn’t crispy enough, move the sheet pan to the top rack and broil on high for 1 minute (keep an eye on it) or bake for longer.
Serve squeezed with lemon and topped with parsley (if using) and black pepper.