Preheat your oven to 425°F (220°C).

Combine chicken thighs, olive oil, honey Dijon mustard, minced garlic, salt, lemon zest, and dry oregano in a large mixing bowl.

Cover and let it marinate in the refrigerator for at least 1 hour.

Thread the marinated chicken onto a vertical gyro spit or skewers.

Place the gyro into the oven and pour 1 cup of water or stock into the baking pan beneath it.

Bake for 75-90 minutes, checking the internal temperature to reach 165°F (74°C).

Let it rest for 10-15 minutes, then slice the chicken into thin strips.

Serve in pita bread with tzatziki sauce and your favorite toppings.