Preheat the oven to 190C/375F/gas 5.
Slice the orange and lemons into 5mm rounds and cut fresh sprigs of rosemary ready to stuff the fish.
Ensure the sea bass is clean inside and out, pat dry with kitchen paper and make four or five diagonal cuts into one side of the fish down to the bone. Fill the cuts with slices of lemon, orange and sprigs of rosemary. Put the remaining fruit and rosemary into the cavity of the fish.
Gently transfer the fish into a foil bag or onto a sheet of tin foil. Drizzle over some olive oil and rub the skin with salt and pepper.
Place the foil bag or tin foil sheet onto a baking tray and pop into the oven. Bake for 20-25 minutes, or until cooked through. Remove from the oven and allow to sit for 2-3 minutes, then place onto a serving plate, carefully open and enjoy with steamed winter vegetables.
1 whole wild Cornish sea bass (1.5kg fish serves four)
2 preserved lemons
1 clementine orange
20g fresh rosemary
Cornish sea salt