Make Marinade: In a small bowl, add ⅓ cup avocado oil4 teaspoons dried oregano leaves, 4 teaspoons garlic, 4 teaspoons red wine vinegar, 2 teaspoons dijon mustard, 2 teaspoons lemon juice, ½ teaspoon kosher salt, ½ teaspoon dried marjoram, ¼ teaspoon garlic powder, ¼ teaspoon ground black pepper, and ⅛ teaspoon dried coriander. Whisk to combine.
Marinate Chicken: Pat 6 bone-in, skin-on chicken thighs dry (trim excess skin, if necessary) and place in a reusable silicone bag or glass container. Pour marinade over top and ensure chicken is fully coated. Seal/cover and place in the refrigerator for 30 minutes or overnight.
Prep: Preheat oven to 400℉.
Sear Chicken: Place a large cast iron skillet on the stove-top and bring to medium-high heat. Add a tiny bit of oil to the pan, just enough to lightly coat the bottom. Once the pan is hot (it should sizzle if you flick some water on it) place the chicken thighs skin-side down into the pan and let sear 3-4 minutes or until the skin is nice and brown.
Bake: Flip the chicken thighs over and then move the skillet to the oven (middle rack and uncovered). Let cook 15-20 minutes or until fully cooked (165℉ internal temperature). Let rest 5-10 minutes before serving.
Grill Option: to grill bring grill up to medium high heat (about 400 degrees F) and ensure grill grates are clean. Grill chicken on direct heat (directly over flame) for 3-4 minutes per side (the bigger the thigh the longer you will need to cook it), flipping once. Remove from grill once the internal temp has reached 165 degrees F. Let rest 5-10 minutes before serving.