Complex sentence: It consists of pieces of fish dipped in melted butter and then dredged in a mixture of herbs and spices, usually some combination of thyme, oregano, chili pepper, peppercorns and salt.
Split into simpler sentences: It consists of pieces of fish dredged in butter and seasoned with a mixture of herbs and spices. The spice mixture usually contains some combination of thyme, oregano, chili pepper, peppercorns and salt.