Set a rack in the center of the oven and pre-heat to 350 degrees F. Butter the bottom and sides of a 10-inch tart pan or springform pan. Place the buttered pan on a baking sheet.
Place the chocolate and salt in a stand mixer, fitted with the whisk, or in a medium size metal bowl if using a hand held mixer.
Use a small, non-reactive saucepan to heat the sugar, rum and liqueur over medium low heat, stirring often, just long enough to melt the sugar. Pour the warm sugar mixture over the chocolate and let sit for about 2 minutes.
Drop in the butter followed by the eggs and whip at medium speed, just long enough to blend, about 2 - 3 minutes. The mixture should look smooth and shiny. It's okay of there are a few bits of unmelted chocolate or butter. Fold in the basket of raspberries and pour the batter into the prepared pan.
Bake for about 35 - 40 minutes, turning the pan from front to back about 2/3 of the way through baking, until the batter has risen and the edges are crackled. Cool and unmold the sides of the tart pan or springform pan and refrigerate for at least 4 hours or overnight.
Note--Run a long, sharp knife under hot water prior to making each slice, for best results.
Serves 8 - 10