Green Cake with Pistachios and White Chocolate Ganache

08 February 2012

Serves 10 to 12

This recipe is excerpted from The Greens Book by Susan Belsinger and Carolyn Dille, Interweave Press, 1995.

Cake:

  • Generous 1 pound spinach, trimmed of large stems and cleaned
  • 4 large eggs, at room temperature, separated
  • 1 teaspoon pure vanilla extract
  • 1/2 cup sugar
  • 1/4 teaspoon salt
  • 1/2 cup cake flour
  • 1/2 cup potato starch flour
  • 1/4 cup powdered sugar

Add the spinach, along with 1/4 cup water, to a large non-reactive pot or pan. Cook over high heat, stirring, until the spinach is just wilted and bright green, about 1 minute. Refresh the spinach under cold water and drain well. Press the spinach lightly to remove most of the excess liquid. Pureé the spinach in a food processor or blender, adding a little of the spinach cooking liquid if necessary, then press the pureé through a fine sieve. Reserve for coloring the cake and frosting.

Add the egg yolks, 1/4 cup of the spinach pureé, and the vanilla extract in an electric mixer. Add 1/2 cup sugar and beat on medium high speed until the mixture is fluffy and ribbons from the beater, about 5 minutes.

Meanwhile, combine the salt and flours and sift. Preheat the oven to 350º F. Butter a 3-inch deep, 9-inch cake pan or springform pan lightly. Line the bottom with baking parchment or aluminum foil and butter.

Beat the egg whites until they hold soft peaks. Add the powdered sugar in two batches, beating well after each addition. Beat the meringue mixture until it holds stiff shiny peaks.

Loosen the yolk mixture with about one-quarter of the whites. Add the flour, alternately with the remaining whites, in three batches.

Pour the batter into the prepared pan and smooth the top. Bake the cake for 25 to 30 minutes, until the sides begin to pull from the pan, and the top springs back when pressed with a finger.

Loosen the sides of the cake from the pan with a spatula, or remove the springform sides. Invert the cake and remove it from the pan, leaving the parchment or foil on the cake.

Set the cake, parchment or foil side down, on a rack to cool to room temperature. The cake may be used when cool, or double-wrapped and refrigerated for a few days, or frozen for up to a month.

Ganache:

  • 1 3/4 cup whipping cream
  • 3 tablespoons spinach pureé
  • 6 ounces white chocolate, chopped fine

In a heavy-bottomed, non-reactive saucepan, scald the cream with the spinach puree. Remove from heat and let stand for 2 or 3 minutes. Pour the scalded cream and spinach mixture through a strainer into a bowl. Sprinkle the white chocolate over the hot cream, and stir it into the cream as it melts. Stir until all the chocolate is melted and the mixture is glossy and smooth. Lay a piece of plastic wrap on the surface of the ganache and refrigerate until well-chilled. This will take about 2 hours, but you can do this up to 24 hours ahead.

With a whisk or the whisk attachment on an electric mixer, whip the cold ganache until stiff peaks just start to form, just as you would for whipped cream. It will be too soft if you don't whip it enough, if you whip it too much it will separate. Once you whip the ganache, you should be prepared to assemble the cake.

Assembling the cake:

1/2 cup unsalted, shelled pistachio nuts, lightly toasted and chopped medium-coarse.

When the cake has cooled completely, cut it into 3 thin horizontal layers with a serrated knife. Place the bottom layer of cake on the platter and frost it with about one-quarter of the ganache. Sprinkle the frosting with about one-third of the pistachios.

Continue layering and frosting the cake, sprinkling the pistachios only on the two bottom layers. After the top has been frosted, frost the sides of the cake. Lightly press the remaining pistachios into the frosting on the bottom layer, where it meets the platter. Refrigerate the cake for at least an hour, or until ready to serve. Remove the cake from the refrigerator about 15 to 20 minutes before serving.