We tested this recipe with Lindt, Valrhona, Ghirardelli, and Callebaut bittersweet chocolates, all of which worked equally well. Our favorite, however, was Valrhona, which made for an especially rich-flavored gianduia.

　　For this recipe you will need heavy-duty foil (thicker and wider than regular foil) to waterproof the springform pan.

　　

Ingredients

Makes 12 to 14 servings

　　9 ounces fine-quality bittersweet chocolate (not unsweetened)

　　7 ounces fine-quality milk chocolate

　　1 cup Nutella * (chocolate-hazelnut spread; from a 13-ounce jar)

　　3/4 cupunsweetened hazelnut butter **

　　6 large eggs

　　1/2 cup superfine granulated sugar

　　1 cup well-chilled heavy cream

　　Accompaniment: whipped cream

　　

Step 1

Preheat oven to 350° F and butter a 10-inch springform pan. Wrap bottom and side of pan with a large piece of heavy-duty foil to waterproof.

　　

Step 2

Chop chocolates into small pieces and melt in a double boiler or a metal bowl set over a saucepan of barely simmering water, stirring until smooth. Remove top of double boiler or bowl from heat and stir in Nutella and hazelnut butter until combined well.

　　

Step 3

In a large bowl of a standing electric mixer or in a large bowl with a handheld mixer beat eggs until frothy, about 1 minute. Gradually add sugar, beating mixture at high speed until thick and pale and it holds a slowly dissolving ribbon when beaters are lifted, about 4 minutes if using a standing mixer and about 8 minutes if using a hand-held mixer. Pour chocolate mixture into egg mixture and stir until combined well. In a chilled bowl beat cream until it holds soft peaks and fold into batter gently but thoroughly.

　　

Step 4

Pour batter into springform pan and put springform pan in a roasting pan. Add enough hot water to roasting pan to reach halfway up side of springform pan. Bake cake in middle of oven 1 hour and 10 minutes. Turn off oven and let cake stand in oven 40 minutes. Remove springform pan from water and cool cake in pan on a rack 30 minutes. Remove side of pan from cake. Let cake cool completely before serving.

　　

Step 5

Serve cake with whipped cream. Cake keeps, covered and chilled, 3 days. Cake served at room temperature will have a texture reminiscent of mousse; chilled cake will be more fudgelike.

　　

Step 6

Available at specialty foods shops and many supermarkets.

Step 7

** Available for purchase from Dundee Orchards, P.O. Box 327, Dundee, OR 97115, (503) 538-8105.