Too good to call Passover cake bête noire

Too Good to Call Passover Cake Bête Noire
(Flourless Chocolate Cake)

8 ounces unsweetened chocolate, very coarsely chopped
4 ounces semisweet chocolate, very coarsely chopped
1 1/3 cups sugar
1/2 pound (2 sticks) unsalted butter, at room temperature, cut into small pieces
5 extra-large eggs

1. Preheat the oven to 350°F. Butter a 9-inch round cake pan (not a springform), line it with a round of parchment paper, and butter the paper.

2. Place both chocolates in a food processor and process until chopped.

3. Combine the sugar and ½ cup water in a saucepan and bring to a rolling boil. Stir to dissolve the sugar.

4. With the processor on, add the boiling sugar syrup to the chocolate through the feed tube. Add the butter, piece by piece, followed by the eggs. Process only until very smooth.

5. Pour the mixture into the prepared cake pan. Set the pan in a larger baking pan, and fill the larger pan with warm water to reach halfway up the sides of the cake pan. Carefully transfer the pan to the oven, and bake on the center oven rack until a sharp knife inserted in the center comes out clean, 25 to 30 minutes. Remove the cake pan from the larger pan and transfer it to a wire rack to cool for 10 minutes.

6. Run a sharp knife around the edges of the pan. Cover the pan with plastic wrap, and invert it onto a baking sheet. Lift off the pan and peel off the parchment paper. Then invert a cake plate over the cake, and invert the plate and baking sheet together, so the cake is now right side up. Remove the plastic wrap.

7. Serve the cake warm, cold, or at room temperature. It will keep, covered, in the refrigerator for up to 1 week.

Serves 12 or more