Soak bread slices in milk, drain in a sieve for at least 4 hours, and squeeze out excess liquid.
Blanch tomatoes in boiling water for 1-2 minutes, peel, quarter, and remove seeds.
Whisk 60ml olive oil with white wine vinegar and season to create a vinaigrette.
Marinate the tomato quarters in 60ml of the vinaigrette for 30 minutes.
Process basil, parsley, 15ml olive oil, breadcrumbs, soaked bread, parmesan, and garlic into a paste.
Divide the stuffing paste into 8 or 12 equal-sized balls.
Place a stuffing ball inside each sardine and secure the fillets with cocktail sticks.
Season the stuffed fish with salt and pepper.
Heat 15ml olive oil and fry half the sardines until browned on one side for 2 minutes.
Flip the fish and cook for 2 minutes more until the stuffing is hot and the fish is golden.
Keep the cooked sardines warm while repeating the frying process with the remaining oil and fish.
Remove cocktail sticks from the sardines before serving.
Dress rocket leaves with 30ml of vinaigrette and arrange tomatoes and olives on plates.
Top rocket with sardines, sprinkle with chives, and drizzle with the remaining vinaigrette.