1. Score and season the branzino fillets. Heat a large skillet and sear the fillets, one to two at a time, skin side down. Only sear the skin side, then remove from the pan and reserve for later.
2. Once all the fillets are seared, add the margarine, onion, and fennel and sauté. Deglaze with the cooking wine. Add the olives and lemon juice and stir to combine. Return the fillets to the pan skin side up. Cook for four to five minutes.
3. Drizzle the white truffle oil over the fish and season with salt and pepper to taste. Garnish with the finely chopped parsley and dill and serve in the pan family style.
4. Enjoy with a starch of your choice such as mashed potatoes or rice.