Spicy Oven Fried Chicken

1 1/4 C buttermilk
1/4 C extra virgin olive oil
3 T hot pepper sauce
2 T Dijon mustard
2 garlic cloves, minced
2 t salt
1/2 t ground black pepper
1 lg onion, sliced
1 C dry unseasoned breadcrumbs (Panko japanese breadcrumbs work great!)
1/3 C grated Parmesan cheese
1/4 C all purpose flour
2 t dried thyme
1/2 t paprika
1/2 t cayenne pepper
3 T butter, melted