To make these chicken gyros, start by preheating your oven to 375 F.
Prepare the chicken by patting the chicken thighs dry.
Then, add them to a bowl alongside the greek yogurt, mashed garlic, olive oil, lemon juice, Italian seasoning, cumin, and paprika. Toss until the chicken is fully coated in the seasonings.
Cover the bowl, then transfer it into the refrigerator for a minimum of 30 minutes, but at least 3-4 hours, until the flavors have marinated into the chicken.
Once the chicken is done marinating, remove it from the fridge.
Grease the vertical spit with oil, then layer the chicken thighs on it.
Place the spit on the lower rack of the oven and allow the chicken to bake for 1.5 hours, or until the internal temperature reaches 165 F. Be sure to watch the chicken carefully - if it gets too browned on the top, around the 50-60 minute mark, remove the spit from the oven, cover the top of chicken with a small piece of foil, and return it from the oven.
Once the chicken is done, remove it from the oven and use a spoon to scoop the juices onto the chicken.
Slice the chicken, then add it to your favorite recipes, and enjoy!