Preheat the oven to 350 degrees.
Sift the first 4 ingredients together in a small mixing bowl.
In a double-boiler or microwave, gently heat the chocolate until its mostly melted. (The chocolate will continue to melt after it is removed from the heat.)
Stir the butter, eggs and sour cream into the chocolate.
Make a well in the dry ingredients. Carefully pour the chocolate mixture inside the well, stirring with a fork until just blended.
Spoon the batter into the prepared Not-Too-Sweet Crust.
Bake for 30 minutes.
Allow the cake to rest for 5 minutes. Remove the sides from the springform pan.
Cover the cake with a thick layer of warm Caramel Topping.
Sprinkle with fleur de sel just before serving.
½ cup unsweetened cocoa powder
¾ cup sugar
¼ tsp. salt
4 oz. high-quality 60-percent cacao bittersweet chocolate (Ghiradelli or other)
1½ sticks unsalted butter, melted
3 large eggs, whisked
½ cup sour cream
Not-Too-Sweet Crust (Click here for the recipe.) Caramel Topping (Click here for the recipe.) Fleur de sel
This article appears in Nov 1-30, 2011.