Preheat your oven to 400°F (200°C).
In a bowl, mix lemon juice, lemon zest, black pepper, garlic powder, onion powder, olive oil, and salt.
Place the chicken thighs in a baking dish.
Pour the lemon pepper mixture over the chicken, ensuring even coverage.
Let the chicken marinate for about 15 minutes for better flavor.
Arrange lemon slices on top of the chicken for added zest.
Bake in the preheated oven for 25-30 minutes or until the chicken is cooked through.
Check that the internal temperature reaches 165°F (75°C).
Remove from the oven and let the chicken rest for 5 minutes.
Garnish with fresh parsley before serving.