Bittersweet Chocolate-Rum Icebox Cake

Bittersweet Chocolate-Rum Icebox Cake

Here’s a stunning chocolate rum icebox cake that’s understated simplicity at its best. Great for entertaining, it serves 16 and can be made in advance. In this soufflé-dish version, rum-dipped ladyfingers surround a rich, bittersweet-chocolate mousse, with an extra layer of cookies running through the middle. After the cake is made and chilled (no baking involved), it’s inverted onto a cake plate, ready for your finishing touches. A dusting of powdered sugar? A sprinkling of cocoa powder? If not, chocolate curls or a satiny ribbon of dark chocolate sauce also make an elegant statement.–Sara Perry and Jane Zwinger

Bittersweet Chocolate-Rum Icebox Cake

  • Quick Glance
  • 50 M
  • 2 H, 20 M
  • Serves 16
5/5 - 1 reviews
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  • For the chocolate curls
  • 1 chocolate block, such as Scharffen Berger 9.7-ounce home baking bar
  • For the icebox cake
  • 3/4 cup granulated sugar, divided
  • 3/4 cup plus 2 tablespoons water
  • 3/4 cup light rum
  • About 32 ladyfingers (two 7-ounce packages)
  • 5 ounces premium dark chocolate, chopped
  • 1/2 cup powdered sugar
  • 2 large eggs, separated and divided
  • 1/2 cup unsalted butter, at room temperature, plus more for the dish
  • 1 large egg white
  • Unsweetened cocoa powder and powdered sugar, for dusting
  • Chocolate curls, for garnish


  • Make the chocolate curls
  • 1. Place the chocolate in a warm spot at room temperature to soften slightly, about 1 hour. Drag a sharp, serrated vegetable peeler in one motion down one side of the bar from top to bottom to create the curl.
  • Make the icebox cake
  • 2. Butter a 2-quart soufflé dish. Cut a circle of parchment to fit the bottom and press into place. Cut a strip of parchment the same width as the height of the soufflé dish. Fit it around the sides and press into place.
  • 3. In a small saucepan over medium-high heat, combine 1/2 cup of the sugar and 3/4 cup of the water and boil for 2 minutes. Remove from the heat and stir in the rum. Let cool slightly. Dip (do not soak) enough ladyfingers in the sugar syrup, one at a time, to stand, side-by-side, around the inside of the soufflé dish. To line the bottom of the dish (which will be the top of the cake once it is unmolded), dip and coat 4 to 5 ladyfingers in the syrup, cutting their ends at an angle to make them fit. (Remember, they form the cake’s top so you will want an attractive placement.) Reserve the remaining rum mixture.
  • 4. Place the chocolate and the remaining 2 tablespoons water in a medium heatproof bowl and set in a wide pan or skillet of hot water. Set aside for 5 minutes, stirring 4 or 5 times, and let it melt completely. Stir until smooth. Gradually stir in the powdered sugar. Add the 2 egg yolks, one at a time, beating well after each addition. Add the 1/2 cup butter, 2 to 3 tablespoons at a time, stirring until each addition is melted. When all is combined, remove from the heat and let cool for 30 minutes.
  • 5. In a stand mixer fitted with the whisk attachment, whisk the 3 egg whites until foamy. Increase the speed to medium-high and gradually add the remaining 1/4 cup sugar. Increase the speed to high and beat until stiff, but not dry, peaks form. Do not overheat. Gently fold one-quarter of the beaten egg whites into the chocolate mixture to lighten it. Fold in the remaining egg whites until just incorporated and no large streaks of egg white remain.
  • 6. Spread half the chocolate mixture into the prepared dish. Dip and coat 4 to 5 more ladyfingers in the syrup and cut to fit, creating a middle layer. Spread the remaining chocolate mixture over the ladyfingers. Dip and coat the final 4 to 5 ladyfingers to cover the top and gently press into place. Cover and refrigerate overnight.
  • 7. To serve the icebox cake, invert the dish onto a serving plate. The cake will slip out of its lining. Carefully peel the parchment paper off the bottom of the cake. To garnish, dust the top of the cake with powdered sugar, cocoa, or a combination of both. For added panache, cap the top with a crown or garland of chocolate curls.

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  1. I made this, and what I did, rather than dip the ladyfingers was to use the liquid and brush it on and it worked perfectly.

    1. Unfortunately, savoiardi are often called ladyfingers, so the terminology gets confusing, but they are not exactly the same. It’s really a matter of degree of dryness. Savoiardi are dry, crisp Italian cookies, not quite as dry as biscotti, but dry enough to be crunchy, used in many Italian desserts such as tiramisu. They are found in grocery stores and Italian markets and hold up well to soaking. Ladyfingers are made from similar ingredients, but are softer, more cake-like. That’s because they are, essentially, a type of French sponge cake. They can be found in supermarkets and some bakeries.

      It can be tricky to use them interchangeably since ladyfingers don’t hold up as well as savoiardi to soaking. However, homemade versions of either can, of course, be made more or less dry and crisp, depending on proportions and baking time.

      If you use savoiardi in this recipe, they would soften from the soaking and from the mousse. Ladyfingers would be much softer to begin with so you may want to leave them out overnight to dry out a bit before soaking them in this recipe. In any case, I don’t think they would fall apart or collapse because they’d adhere to the sides of the mousse as long as it has been well chilled before unmolding.

    2. Hello, Lisa. “Savoiardi” is the Italian name for ladyfingers, and it indicates the history of the biscuit, which was created at the French court of Savoy, some sources say as early as the 11th century (others say the 15th). You may also see ladyfingers referred to “boudoir biscuits” or “biscuits à la cuillère” in French. The main thing to avoid is using soft sponge fingers instead of the dry ones.

      For the recipe in question, the dry version of ladyfingers, which are interchangeable with savoiardi, should be used. The two can be used interchangeably in recipes that require a dry biscuit to be dipped into a sugar syrup or other flavored liquid, such as coffee when making a traditional tiramisu. Of course, the inconsistent use of the name as pertains to store-bought biscuits doesn’t help anyone, given that the term is also used for the already-soft, sponge-cake fingers commercially known as “ladyfingers.”) I make tiramisu and charlottes a lot, and find that using soft sponge cakes is a mistake most of the time.

      In a recipe that calls for dipping into syrup or liqueur, the dry ones are better; they absorb a lot of liquid and become, therefore, like the sponge fingers, but with the flavor of whatever you’ve dipped them in. You really don’t want to soak them, but rather dip them. One second is often enough, or at most a second per side; you don’t want them to get too soggy.

      I have actually made this recipe, and I think it’s grand. Hope you feel the same.

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