Makes one 8-inch cake that will serve 8 people. (For a dramatic 10-inch cake double the recipe and use a 10-inch cake pan or springform pan.)
- Butter and flour for coating the pan
- 8 ounces bitter or semi-sweet chocolate (at least 70% cocoa solids), coarsely chopped (fresh, fragrant chocolate is essential)
- 6 tablespoons (3/4 stick) unsalted butter
- 2/3 cup all-purpose flour
- 1/2 teaspoon baking powder
- 1/4 teaspoon Kosher salt
- 2 large eggs
- 2 teaspoons vanilla extract or half vanilla extract and half Cognac
- 1/2 cup sugar
- 1 or 2 teaspoons cocoa powder
Position the rack in the middle of the oven. Preheat the oven to 350°.
Rub the inside of an 8-inch cake pan or a springform pan with butter. Swirl a few teaspoons of flour around to coat completely. Invert the pan and tap out the excess.
Combine the chocolate and butter in the top of a double boiler over simmering water. (Or, alternatively, combine in a medium, heavy saucepan and set on a flame tamer/diffuser over very low heat). Stir occasionally until the chocolate is melted. Set aside to cool.
Meanwhile, sift the flour, baking powder, and salt into a bowl; whisk well and set aside.
Combine the eggs, vanilla extract in a large bowl. Whisk until foamy. Add the sugar and whisk until light and frothy, 1 minute. Blend in the chocolate mixture. Add the flour mixture in 2 batches, whisking to blend completely each time.
Pour the batter into the prepared pan. Bake 22 to 25 minutes until a skewer inserted 1 inch from the edge comes out clean. When inserted in the center, a bit of moist batter will cling to it. Do not over bake.
Cool the cake on a rack 10 minutes, then invert onto a plate. Invert back onto the rack so the shiny side is up. Cool the cake completely before sliding it onto a serving plate. Sift the cocoa over the top.