Blanch the grape leaves in a pot of boiling water for 3 minutes. Remove with a slotted spoon to a colander and rinse under cold water.

Lightly oil an ovenproof glass baking dish large enough to hold the sardines snuggly in 1 layer.

Preheat the oven to 350˚F (180˚C).

Heat 1 tablespoon olive oil in a medium skillet over medium heat, add the scallions and garlic, and cook until soft, about 5 minutes. Add the tomatoes, wine, and Mastiha powder, and cook, uncovered, for 5-7 minutes, until the tomatoes loose some of their water. Toss in the parsley and mint and remove from the heat.

Season each sardine with salt and pepper to taste and wrap each in a grape leaf. Place seam side down in the baking dish. Distribute the sauce evenly over the sardines. Drizzle in the remaining olive oil. Sprinkle with the paprika. Cover the pan with foil and bake for about 35 minutes, until the fish is flaky and tender. Remove from the oven and place 3 sardines on each plate, with the sauce spooned on top.