Preheat your oven to 425°F (220°C).

In a large mixing bowl, combine the chicken thighs with olive oil, honey Dijon mustard, minced garlic, salt, lemon zest, and dried oregano to create a marinade.

Thread the marinated thighs onto a vertical gyro spit plate, alternating each piece's orientation.

To make a DIY gyro support, cut an onion in half and place it on a lined baking sheet. Use skewers to insert each marinated chicken thigh into the onion.

Place the gyro in the oven and add 1 cup of water or stock to the base of the baking sheet.

Bake for 75-90 minutes, checking periodically.

Once fully cooked, let the gyro rest for 10 minutes before slicing.