Preheat the oven to 400°F (200°C/Gas 6).
Scale and gut the sardines, then remove the heads and central spine.
To prepare the filling, wash and finely chop the parsley and mint leaves, reserving some for the garnish. Place in a bowl with the brocciu, egg and garlic, then stir until well blended. Season with salt and pepper.
Open the sardines, skin side down, and place a spoonful of filling on one side of each. Close the sardines.
Place the stuffed sardines in a baking dish greased with olive oil.
Bake for 10-12 minutes, until the fish is cooked through.
Season with pepper, garnish with a few parsley and mint leaves, and serve immediately.