Heat the oven to 450°F. Using cooking spray to coat a glass baking pan. (I use a 10 x 15 baking pan.)

Pat the chicken thighs dry with paper towels. Trim off the excess fat and skin.

In 2 small bowls, mix half the spices in each bowl. So each bowl will have 2 teaspoons salt, 1 teaspoon pepper, 1 teaspoon oregano, 1 teaspoon basil, and 1 teaspoon garlic powder.

In a medium mixing bowl, add the potatoes, mushrooms, onions, and olive oil and mix until everything is lightly coated with oil. Sprinkle the remainder of the seasoning mix from 1 bowl on the vegetables and stir until everything is mixed well.

Pour the contents of the bowl into the baking pan and spread it around evenly.

Sprinkle the seasoning mixture from the other bowl liberally on both sides of the chicken thighs. Place the thighs in the baking pan skin side up on top of vegetables.

Place the pan in the oven uncovered and cook for 30 minutes. Since the chicken thighs will put off a lot of liquid, you will need to drain some or all of the liquid out of the pan before returning it to the oven to finish the cooking.

Stir the potato mixture and return it to the oven to cook for another 30 minutes.

The skin on the thighs and most of the vegetable should be crispy. Use a meat thermometer to make sure the thighs are 165° F. If the meat is still underdone, cook for another 15 minutes and test again.

Garnish with fresh chopped parsley if desired.