Buttermilk Fried Chicken

Name: Buttermilk Fried Chicken
Ingredients: 2 cups buttermilk (can also use plain yogurt thinned with a little milk); 1 large onion , sliced; 1/4 cup mixed fresh herbs (parsley, thyme, tarragon), chopped, or a teaspoon each of the dried herbs.; 1/2 teaspoon paprika; 1/2 teaspoon cayenne pepper; 3 pounds chicken parts (thighs, drumsticks, wings, breasts), bone-in, skin-on; 2 cups cooking oil (such as canola or peanut oil); 2 cups all-purpose flour; 1/2 teaspoon garlic salt; 1/2 teaspoon onion salt; 1 teaspoon cayenne pepper; Kosher Salt and freshly ground black pepper to taste