1. Make the Crust:

1. Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper, leaving an overhang for easy removal.
2. In a large bowl, beat the softened butter and granulated sugar until creamy.
3. Add the flour and salt, mixing until the dough comes together.
4. Press the dough evenly into the prepared baking pan. Prick the crust lightly with a fork.
5. Bake for 15-18 minutes, or until lightly golden. Remove from the oven and let it cool slightly.

2. Prepare the Raspberry Filling:

1. In a saucepan over medium heat, combine the raspberries, sugar, cornstarch, and lemon juice.
2. Cook, stirring frequently, until the mixture thickens and becomes jam-like (about 5-7 minutes). Remove from heat and let cool slightly.

3. Assemble the Bars:

1. Spread the raspberry filling evenly over the cooled crust.

4. Make the Dark Chocolate Topping:

1. In a microwave-safe bowl, combine the dark chocolate and heavy cream. Heat in 20-second intervals, stirring between each, until smooth and melted.
2. Drizzle or spread the melted chocolate over the raspberry layer.

5. Chill and Serve:

1. Refrigerate the assembled bars for at least 2 hours, or until the chocolate is set.
2. Use the parchment overhang to lift the bars out of the pan. Slice into squares or rectangles and serve chilled or at room temperature.