Finely grated baking chocolate makes this cake world class! Naturally low carb 1.5 g per slice and only 2 WW points!
- 1–1/2 cups, divided superfine sugar
- 3/4 cup cake flour, lightly spooned and leveled off (or 1 cup, sifted into the cup and leveled off)
- 1/4 teaspoon salt
- 16 large egg whites, at room temperature, or 2 cups
- 2 teaspoons cream of tartar
- 4 teaspoons pure vanilla extract
- 2 ounces fine-quality unsweetened or 99% cacao chocolate, chilled, finely grated, refrigerated
- SPECIAL EQUIPMENT: One ungreased 10-inch (16 cups) two-piece metal tube pan or 1 long-necked glass wine or soda bottle, or a large inverted metal funnel that will fit into the opening at the top of the pan. (Have this ready before baking and weight it by filling it with sugar or marbles to keep it from tipping.)
- PREHEAT THE OVEN: Twenty minutes or more before baking, set an oven rack in the lower third of the oven and preheat the oven to 350°F/175°C.
- PREPARE THE SUGAR, FLOUR, AND SALT: In a small bowl, whisk together half the sugar, the flour, and salt until evenly combined. Sift the remaining sugar onto a piece of wax paper.
- BEAT THE EGG WHITES INTO A STIFF MERINGUE: In the bowl of a stand mixer fitted with the whisk beater, beat the egg whites on medium speed until foamy. With the mixer off, add the cream of tartar. Raise the speed to medium-high and beat until soft peaks form when the beater is raised. Gradually beat in the sifted sugar and continue beating on medium-high speed until very stiff peaks form when the beater is raised slowly. Beat in the vanilla until combined.
- MAKE THE BATTER: Dust (lightly sprinkle) the flour mixture over the beaten whites, 1/4 cup at a time (if using cake flour, sift it over the whites). With a large balloon whisk, slotted skimmer, or large silicone spatula, fold in the flour mixture quickly but gently. It is not necessary to incorporate every speck until the last addition. Fold in the grated chocolate until evenly incorporated. Using a long narrow spatula or silicone spatula, spread a thin layer of batter onto the sides of the prepared pan to ensure smooth sides. Empty the rest of the batter into the pan. In a 16-cup pan, it will be 1/2-inch from the top of the rim. Run a small metal spatula or knife through the batter to prevent air pockets and smooth the surface evenly.
- BAKE THE CAKE: Bake for 30 to 40 minutes, or until golden brown, a wire cake tester inserted between the tube and the side comes out clean, and the cake springs back when lightly pressed in the center. (A wooden toothpick will still have a few moist crumbs clinging to it.) During baking, the center will rise about 2 inches above the pan, but it will sink to almost level with the pan when done. The surface will have deep cracks, like a souffle.
- COOL AND UNMOLD THE CAKE: Invert the pan immediately, placing the tube opening over the neck of the bottle to suspend it well above the countertop. Cool completely in the pan, about 1-1/2 hours. Loosen the sides of the pan with a long narrow spatula and remove the center core of the pan. Dislodge the cake from the bottom and center core with a metal spatula or thin sharp knife. (A wire cake tester or wooden skewer works well around the core. To keep the sides attractive, press the spatula firmly against the sides of the pan, moving the spatula up and down as you go around it.) Invert the cake onto a flat plate covered with plastic wrap that has been coated lightly with nonstick cooking spray and reinvert it onto a serving plate. Allow the cake to sit for 1 hour, or until the top is no longer tacky. Then cover it with a cake dome or wrap it airtight. It keeps for 3 days at room temperature and for 10 days refrigerated. Freezing toughens the texture. The cake is also lovely decorated simply with a light sprinkling of cocoa or lacy drizzles of melted chocolate. Do not serve this cake with sauce as it would fall apart.