Chicken Shashlik - Rub the Beef

Ingredients

• 4 yellow onions (peeled)
• 1 bulb garlic (peeled)
• 1/4 cup apple cider vinegar
• 1/4 cup chicken stock (Water can be substituted)
• 2 teaspoons lemon juice (juice from half a lemon)
• 4 bay leaves
• 1 tablespoon ground black pepper
• 1 tablespoon oregano (dried oregano is fine)
• 1 teaspoon kosher salt
• 4 pounds chicken thighs (boneless, skinless preferred)