Chicken Thighs in the Oven

Name: Chicken Thighs in the Oven
Prep time: 10 min
Cook time: 35 min
Total time: 45 min
Cuisine: American, Italian
Ingredients: 2 1/4 pounds bone-in, skin-on chicken thighs (about 4); 3 garlic cloves (minced (about 1 tablespoon)); 3 tablespoons extra-virgin olive oil (divided); 2 teaspoons Italian seasoning; 1 teaspoon dried rosemary; 1 lemon (zest and juice); 1 1/2 teaspoons kosher salt (divided); 1/2 teaspoon ground black pepper (divided); 2 small or 1 extra large onion; 1/2 tablespoon sherry vinegar or red wine vinegar; Chopped fresh parsley (or tarragon or thyme, plus additional for serving)