http://www.kingarthurflour.com/recipes/passover-flourless-chocolate-cake-recipe
This cake features both chocolate and cocoa; the combination gives it a rich, dark color, and deep chocolate flavor. A chocolate ganache glaze takes it over the top. And, since it contains neither flour nor leavening, it’s perfect for Passover. Step-by-step photos illustrating how to make this cake are available at Bakers’ Banter, our King Arthur blog.
Cake
1 cup (6 ounces) chopped semisweet chocolate or chocolate chips
1/2 cup (1 stick, 4 ounces) unsalted butter
3/4 cup (5 1/4 ounces) granulated sugar
1/8 teaspoon salt
1 to 2 teaspoons espresso powder, optional
3 large eggs
1/2 cup (1 1/2 ounces) unsweetened cocoa powder, Dutch-process preferred
Glaze
1 cup (6 ounces) chopped semisweet chocolate or chocolate chips
1/2 cup (4 ounces) heavy cream
Topping
1/4 cup sliced almonds, toasted in a 350°F oven till golden brown, about 10 minutes
Preheat the oven to 375°F. Lightly grease an 8" round cake pan; cut a piece of parchment or waxed paper to fit, grease it, and lay it in the bottom of the pan.
To make the cake: Put the chocolate and butter in a microwave-safe bowl, and heat till the butter is melted and the chips are soft. Stir until the chips melt, reheating briefly if necessary. You can also do this over a burner set at very low heat. Transfer the melted chocolate/butter to a mixing bowl.
Add the sugar, salt, and espresso powder. Espresso enhances chocolate’s flavor much as vanilla does; using 1 teaspoon will simply enhance the flavor, while 2 teaspoons will lend a hint of mocha to the cake. Add the eggs, beating briefly until smooth. Add the cocoa powder, and mix just to combine.
Spoon the batter into the prepared pan. Bake the cake for 25 minutes; the top will have formed a thin crust. Remove it from the oven, and cool it in the pan for 5 minutes. Loosen the edges of the pan with a table knife or nylon spreader, and turn it out onto a serving plate. The top will now be on the bottom; that’s fine. Also, the edges will crumble a bit, which is also fine. Allow the cake to cool completely before glazing.
To prepare the glaze: Combine the chocolate and cream in a microwave-safe bowl, and heat till the cream is very hot, but not simmering. Remove from the microwave, and stir till the chocolate melts and the mixture is completely smooth.
Spoon the glaze over the cake, spreading it to drip over the sides a bit. Allow the glaze to set for several hours before serving the cake.
Yield: one 8" cake, 12 rich servings.
Note - the original recipe published a few years ago called for using 1/2 cup confectioners sugar and 1/2 cup granulated sugar. Apparently confectioner's sugar is not kosher so the chef updated the recipe to all granulated sugar. I made it the first way. Additionally the original recipe called for adding 1 teaspoon vanilla to the glaze.
The recipe for the almonds may burn way short of the time stated.