How to Make It
Preheat the oven to 375° and position a rack in the center.
In a large skillet, heat 2 tablespoons of the olive oil over moderate heat. Add the onion and garlic and cook, stirring, until the onion is translucent, 6 to 7 minutes. Add the Swiss chard, season with salt and pepper, and cook, stirring, for 5 to 7 minutes. Remove the pan from the heat and discard the garlic. Stir in the almonds, mint leaves and raisins. Season with salt and pepper, if needed. Let the stuffing cool to room temperature.
Season the sardines with salt and pepper and place on a work surface, vertically, with the tails pointing away from you, skin side down. Divide the stuffing by 4 and spread over the body of each sardine, excluding the tail. Starting from the the part closest to you, roll each sardine up and use a small skewer or a toothpick to secure the tail to the roulade.
Grease an 8-by-8-inch baking pan with 1 tablespoon of olive oil. Put the roulades in the baking pan and drizzle the remaining 1 tablespoon of olive oil over them. Put a lemon slice in between each of the roulades. Transfer to the oven and bake for 7 minutes. Remove the pan from the oven and sprinkle lemon juice and parsley leaves over the roulades. Serve immediately.