Christopher Kimball visited Claire Ptak at London’s Violet Bakery in the first season of Christopher Kimball’s Milk Street Television, for an episode called “The New Baking.” He picked up tips to create this chocolate, prune, and rum cake.
Claire Ptak’s chocolate, prune, and whiskey cake is deliciously gooey at the center. A ratio of 3:1 chocolate to butter — as well as 8 ounces of chopped pitted prunes — got us the same results. We preferred bar chocolates with 60 to 70 percent cacao (especially the Ghirardelli and Guittard brands) to chocolate chips, which contain stabilizers that changed the cake’s texture.
Ptak uses almond flour — not an uncommon ingredient in flourless chocolate cakes like this, but certainly not a common ingredient in American homes. We reworked the cake a bit to leave it out and found the results just as good.
Adding the egg yolks and whites separately made a big difference, too. Whipping the yolks helps maintain the emulsion of chocolate and butter; skipping that step produced an unpleasantly dense cake. And Ptak stressed to us the value of whipping the egg whites to soft peaks and just barely folding them into the batter.
She originally made this cake with Armagnac, then switched to whiskey. We couldn’t easily find the former, and the latter — while delicious once the cake was cooled — tasted harsh when the cake was warm (and this cake begs to be eaten warm). We found dark rum tasted delicious both warm or cool.
Serves 12
INGREDIENTS
- 9 tablespoons salted butter (1 tablespoon softened)
- 8 ounces pitted prunes (about 1½ cups), finely chopped
- ⅓ cup dark rum
- 1 tablespoon molasses
- 12 ounces bittersweet chocolate, finely chopped
- 6 large eggs, separated
- ⅓ cup plus ¼ cup white sugar
- ½ teaspoon kosher salt
TO PREPARE
STEP ONE. Heat the oven to 325°F with a rack in the middle position. Coat the bottom and sides of a 9-inch spring-form pan evenly with the tablespoon of softened butter.
STEP TWO. In a 2-cup liquid measuring cup, combine the prunes, rum and molasses. Microwave until the rum is bubbling, 45 to 60 seconds. Let sit for 15 minutes, stirring occasionally.
STEP THREE. In a medium saucepan over medium heat, melt the remaining 8 tablespoons of butter. Remove from the heat and immediately add the chocolate, then whisk until melted and completely smooth.
STEP FOUR. In a large bowl, whisk together the egg yolks and ⅓ cup of sugar until pale and glossy, about 30 seconds. Slowly add the melted chocolate mixture and continue whisking until smooth. Stir in the prune mixture.
STEP FIVE. Using a stand mixer with a whisk attachment, whip the egg whites and salt on medium-high speed until light and foamy, about 1 minute. With the mixer running, slowly sprinkle in the remaining ¼ cup of sugar and continue to whip until the whites are thick and glossy and hold soft peaks, about 1 minute.
STEP SIX. Whisk ⅓ of the whipped egg whites into the chocolate mixture to lighten it. Gently fold in the remaining whites with a rubber spatula until the batter is marbled but not fully blended. Pour the batter into the prepared pan. If needed, smooth the top with a spatula.
STEP SEVEN. Bake until the edges of the cake are firm and cracked, 35 to 40 minutes. The center will be just set, yet soft to the touch. Cool the cake in the pan on a wire rack for at least 1 hour before serving (the cake will settle and sink as it cools).
NOTE: Don’t over-bake this cake. Don’t be alarmed if the center still jiggles a bit and yields to gentle pressure; the cake will continue to set after it comes out of the oven.
