½lb(2 sticks) lightly salted buttersoftened, plus more for the baking sheet
1tspunsweetened dark cocoa powder
2tbspclover honeyplus more to taste
Preheat the oven to 325°F.
Make the shortbread dough:
In a medium saucepan over very low heat (or in a double boiler), melt the butter and chocolate together, stirring constantly. Remove the pan from the heat and stir in the sugar. Then gently fold the flour and the salt into the chocolate mixture.
Bake the shortbread:
Grease a 15-inch baking sheet with butter. Gently press the dough into an even 1-inch-thick layer on the baking sheet. Bake for 35 to 40 minutes. To test for doneness, insert the tip of a small knife into the shortbread; it should emerge clean. Remove the baking sheet from the oven and allow the shortbread to cool for 5 minutes. Then transfer the shortbread to a cutting board and cut it into 20 squares. Allow them to cool on a wire rack for at least 15 to 20 minutes.
Make the filling and assemble the sandwiches:
In a medium bowl, whisk together the cocoa powder and honey until smooth. Mix in the raspberries, lightly crushing them. Taste, and add more honey if desired. Put half of the shortbread squares on a platter or on individual plates, and spoon the raspberry filling over them. Top with the remaining shortbread squares.