Preheat your oven to 425°F (220°C) and line a large rimmed baking sheet with parchment paper.
Pat the chicken thighs completely dry with paper towels to ensure the arrowroot creates a golden, crispy exterior.
In a small mixing bowl, whisk together the olive oil, arrowroot powder, dried oregano, garlic powder, sea salt, black pepper, lemon juice, and lemon zest.
Place the chicken thighs, broccoli florets, and asparagus spears on the prepared baking sheet.
Drizzle the lemon-herb mixture over the chicken and vegetables, tossing thoroughly with your hands to ensure an even coating.
Spread the ingredients into a single layer, making sure the chicken pieces have space around them for maximum airflow and crispiness.
Bake for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender with lightly charred edges.
Remove from the oven and garnish with freshly chopped parsley before serving immediately.