In a small bowl, mix together the chilli, bay leaves, peppercorns, garlic, mustard seeds and parsley.

Season fish with salt and secret spice and coat with half of the spice mixture.

Set a frying pan over medium heat, add oil and 2 tablespoon of butter.

Sear the fish for about 4 minutes on each side, then remove.

In the same pan, add the rest of the butter and sear onions until they are light brown and cooked through.

Stir in the remaining spice mixture, add vinegar and return the fish to the pan.

Cook for 3 minutes and serve.