12 oz. bittersweet chocolate, chopped
3/4 c. butter, cut into pieces
6 large eggs, separated
12 T. sugar
2 t. vanilla extract
Preheat oven to 350 degrees fahrenheit. Butter a 9 in spring-form pan and line with buttered parchment paper or wax paper.
Melt chocolate and butter in a small saucepan over low heat until melted. Remove from heat and let cool to lukewarm, stirring often.
In an electric mixer fitted with paddle attachment, beat egg yolks and 6 T. of sugar until very thick and pale, about 3 minutes. Fold in the lukewarm chocolate and the vanilla extract.
Using a clean beater or whisk attachment and bowl, beat egg whites until soft peaks form. Gradually add 6 T. sugar, beating until medium-firm peaks form. Fold whites into chocolate mixture, a little at a time. Pour into prepared pan.
Bake until top is puffed and cracked and tester comes out with moist crumbs, about 50 minutes. Cool cake in pan on rack (cake will fall but that’s ok).
Gently press down the crusty top to make an evenly thick cake. Cut around pan sides to loosen cake and remove pan sides. Place a 9 in. diameter flat plate or cardboard round atop cake. Invert cake and peel off the parchment paper.
Salted Buttermilk Caramel Sauce
1/2 c. butter
3/4 c. buttermilk
1 1/2 c. granulated sugar
2 T. corn syrup
1 tsp. baking soda
1 tsp. vanilla
1 1/2 t. large grain sea salt (fleur de sel)
Combine butter, buttermilk, sugar, corn syrup and baking soda in large cooking pot. (it will boil over if pot is too small). Bring ingredients to a boil over medium heat, then reduce temp to a simmer. Cook, stirring frequently for 7-9 minutes. It is done when the caramel sauce is a golden brown. Remove from heat and stir in vanilla.
The caramel will look like this when you need to pull if off the heat:
But will quickly look like this after the addition of vanilla and the bubbles subside with stirring:
Let caramel sauce cool and thicken. Pour cooled caramel sauce over center of cooled chocolate torte, keeping at least 1/2 inch from the edges. Chill torte in freezer for 30 minutes. Remove from heat and sprinkle with sea salt. Serve at room temperature.