DO AHEAD: Can be made 2 days ahead. Keep chilled.
MERINGUES: Preheat oven to 200°F. Line large baking sheet with foil; grease foil lightly. Using electric mixer, beat egg whites and cream of tartar in large bowl until soft peaks form. Gradually add sugar, beating until meringue is stiff and shiny. Fold in half of almonds.
Drop meringue in 8 mounds onto prepared baking sheet. Using back of spoon, make indentation in each mound. Sprinkle meringues with remaining almonds. Bake 1 hour. Turn off oven; leave oven door closed and let meringues dry in oven overnight.
Place meringues on platter or baking sheet and fill each with large scoop of frozen zabaglione. Wrap meringues tightly and freeze at least 8 hours and up to 1 day.
Rewarm chocolate sauce over low heat. Place each filled meringue on plate. Spoon warm chocolate sauce over and serve immediately.
Working with MeringueMeringues are made by beating egg whites to soft peaks, then adding sugar and beating until firm, glossy peaks form. Soft meringue is used as a topping for pies (such as lemon meringue pie) and other desserts, like baked Alaskas, and to add airy lightness to mousses and soufflés. Hard meringues are baked for a long time at a low temperature so they become dry while remaining white. Here are tips to make perfect meringues every time.1. Use egg whites that are at room temperature; they will reach a greater volume.2. When separating the eggs, make sure none of the yolk gets into the whites.3. Your bowl and whisk or beater must also be completely clean. Any trace of yolks or fat on your equipment will make it very difficult to stiffen the egg whites.4. Add cream of tartar or lemon juice to the egg whites before they’re beaten to help stabilize the foam.5. Use an electric mixer or a large balloon whisk and a metal or glass bowl.6. Beat the egg whites to soft peaks, and then gradually add the sugar. Adding the sugar too early will slow down the stiffening process; adding the sugar after the whites have reached stiff peaks could cause the meringue to become too dry.Once the meringue is formed, use it immediately, since it will weep and lose volume quickly. Store hard meringues in an airtight container to maintain their dry, crisp texture.
A dacquoise is one of the greatest French cakes, combining wonderful textures and flavors into one luxurious dessert. Here, crunchy hazelnut meringue layers are sandwiched with a fudgy dark chocolate ganache and a light and creamy white chocolate mousse. This one is rectangular, but you can also make it round. Start preparing this layered treat at least one day before you plan to serve it, as it needs to freeze overnight. 10 servings
Meringue
1¼ cups hazelnuts, toasted, husked, divided
¾ cup sugar, divided
6 large egg whites, room temperature
⅛ teaspoon cream of tartar
Ganaches
2 cups heavy whipping cream, divided
4 tablespoons light corn syrup, divided
24 ounces bittersweet or semisweet chocolate (do not exceed 61% cacao), finely choppedWhite Chocolate Mousse (see recipe)
8 ounces high-quality white chocolate (such as Lindt or Perugina), chopped
24 hazelnuts, toasted, husked
MERINGUE: Preheat oven to 300°F. Line large baking sheet with parchment paper. Draw three 9×5-inch rectangles on parchment. Turn paper over. Finely grind 1 cup nuts with ¼ cup sugar in processor. Coarsely chop remaining ¼ cup nuts; set aside for garnish.
Beat egg whites and cream of tartar in large bowl until foamy. Gradually add remaining ½ cup sugar, beating until stiff and glossy. Fold ground hazelnut mixture into whites in 2 additions. Divide meringue among traced rectangles on parchment, spreading to edges. Bake meringues until crisp and light golden, about 1 hour 30 minutes. Turn oven off; cool meringues in oven 1 hour. Remove from oven.
GANACHES: Bring 1½ cups cream and 3 tablespoons corn syrup to simmer in medium saucepan. Remove from heat. Add bittersweet chocolate; stir until smooth. Chill until slightly thickened but still spreadable, about 1 hour.
Line 9×5×2½ -inch metal loaf pan with plastic wrap, leaving 3-inch overhang on all sides. Run thin knife under meringues to loosen from parchment. Gently transfer meringues to work surface. Using serrated knife and gentle sawing motion, trim each to 8×4-inch rectangle.
Spread ⅓ cup chocolate ganache over each of 2 meringues. Place on baking sheet. Freeze until ganache is set, about 10 minutes. Place third meringue, smooth side down, in prepared loaf pan. Spread half of White Chocolate Mousse over. Sprinkle with reserved ¼ cup chopped hazelnuts. Top with 1 meringue, ganache side down. Spread remaining mousse over. Top with remaining meringue, ganache side down. Fold plastic overhang over cake; freeze overnight. Chill remaining bittersweet chocolate ganache.
Bring remaining ½ cup cream and remaining 1 tablespoon corn syrup to simmer in small saucepan. Remove from heat. Add white chocolate; stir until smooth. Chill just until thick enough to spread, about 30 minutes.
Invert cake onto small baking sheet; remove plastic. Working quickly, spread white chocolate ganache thinly over top and sides of cake. Place 24 hazelnuts around top edge of cake. Freeze cake until frosting is firm, about 30 minutes.
DO AHEAD: Can be made 1 week ahead. Cover cake tightly and keep frozen.
Keep bittersweet chocolate ganache chilled. Before serving, rewarm ganache over low heat, stirring just until liquid.
Serve cake, passing remaining bittersweet ganache as sauce.
Frangelico is used in this mousse to pair well with the hazelnut dacquoise, but other liqueurs can also be used. For instance, if you’re making meringues with almonds or pistachios, use amaretto in the mousse. Be sure the chocolate mixture is completely cool before folding in the whipped cream, or the cream will melt and the mousse won’t have an airy texture. Don’t worry if the mousse is soft at first; it sets up nicely as it chills. Makes about 2½ cups
2 large eggs
⅓ cup sugar
3 tablespoons Frangelico (hazelnut liqueur)
6 ounces high-quality white chocolate (such as Lindt or Perugina), chopped
1 cup chilled heavy whipping cream
Whisk eggs, sugar, and Frangelico in large metal bowl to blend. Set bowl over saucepan of simmering water (do not allow bowl to touch water); whisk constantly until mixture thickens and candy thermometer inserted into mixture registers 140°F for 3 minutes, about 7 minutes total. Remove bowl from over water. Add white chocolate; whisk until smooth. Cool completely, whisking occasionally. Beat cream in medium bowl to medium-firm peaks. Fold whipped cream into white chocolate mixture in 3 additions (mixture will be soft). Chill until spreadable, about 3 hours.
Baked Alaskas are like an edible magic trick: Sponge cake and a layer of ice cream are covered with meringue, then browned in a hot oven—without melting the ice cream. These individual baked Alaskas pair chocolate cake with purchased strawberry ice cream and a meringue topping. Even better: They can be assembled up to two days ahead. Makes 6
6 ounces bittersweet or semisweet chocolate (do not exceed 61% cacao), chopped