1. Preheat oven to 400ºF. Spray a large sturdy baking sheet with cooking spray or for easier clean-up, line with parchment paper or heavy-duty foil.
2. Place the chicken on prepared baking sheet. Season with salt and black pepper to taste.
3. In a small bowl, combine soy sauce, lemon juice, butter, and cilantro together. Drizzle 1/3 of the sauce over the chicken.
4. Bake for 5 minutes (20 for chicken thighs). Meanwhile, combine the seasonings in a small bowl and set aside.
5. After 5 minutes, remove baking pan from the oven, flip the chicken and place the asparagus and broccoli along with the sides of the chicken. Sprinkle the chicken and vegetables with seasonings and drizzle sauce over the vegetables and some more on the chicken (reserve 1 teaspoon for the end).
6. Return the pan back to the oven and bake for another 10-15 minutes, or once the chicken is cooked through and has reached an internal temperature of 165ºF. If the chicken is still not cooked to internal temp. 165 after 15 minutes, you may want to remove the vegetables first before putting the chicken back in the oven, so they don't overcook. This is just depending on your level of preference for the cooked vegetables.
7. Drizzle the chicken with additional sauce and turn the oven to broil for -2 minutes, until the chicken has a nice brown color (watch closely so the chicken does not burn).
8. Sprinkle with chopped parsley, if desired and serve hot.