In a small bowl, mix the raisins with the lemon juice, scallion, parsley, bread crumbs, chopped ham and ground fennel. Season with salt and pepper. Open a sardine and place a rounded teaspoon of the filling on one side of the fish. Close the sardine, pressing the halves together firmly. Repeat with the remaining sardines and filling.

Spread flour in a shallow bowl. Place the eggs in another shallow bowl and beat the water into the eggs. Dredge the sardines in the flour, then dip them into the egg mixture to thoroughly coat, letting the excess drip off. Dredge the sardines again in the flour and shake off any excess.

In a large skillet, heat 1/4 inch of olive oil until shimmering. Add half of the sardines and fry over moderately high heat until golden brown and crisp, about 2 minutes per side. Drain the sardines briefly on paper towels and transfer to plates. Repeat with the remaining sardines.