cake - Walnut Roll Cake

By tinathorn

Ingredients

• For the cake:
• 5 or 6 eggs, separated, preferably at room temperature (consider using pasteurized eggs; see Notes)
• 5 1/2 ounces (~1 1/2 cups) ground walnuts
• 1/2 cup sugar
• pinch of salt
• 1/2 teaspoon baking powder
• ~1 tablespoon butter for greasing baking pan
• For the filling:
• 6 1/2 ounces (~1 3/4 cups) ground walnuts
• 1/2 cup warm milk
• 1/4 pound (1 stick) unsalted butter
• 2/3 cup sugar
• 2 tablespoons Cognac
• 1 cup heavy cream, whipped
• For the garnish:
• confectioner’s (powdered) sugar (1/2 cup or so)
• sprigs of mint and/or berries (optional; strawberries and blackberries both work well)

Details

Adapted from kitchenriffs.com

Preparation

Step 1

For the cake:
Set the eggs out to warm to room temperate (not strictly necessary, and a step we often skip, but the whites beat better if they’re not cold; see Notes for what to do if you haven’t let the eggs warm before starting).
When ready to proceed, preheat oven to 375 degree F.
Butter a half-sheet pan or jelly roll pan (11 x 17 inches), then line the pan with parchment paper or waxed paper. Be sure to leave about 2 inches of paper hanging over at each end. Butter the paper.
Grind the walnuts finely (it’s easiest to do this using a food processor). I usually grind 12 ounces of walnuts at one time, use 5½ ounces in this step, and then set aside 6½ ounces for the filling.
Separate the eggs (see Notes).
Place egg yolks in the bowl of a stand mixer (or in a medium bowl if beating by hand). Beat the egg yolks, and after a minute gradually begin to add the sugar and a pinch of salt. In a few minutes (perhaps 5) the eggs will become light and creamy. Add baking powder and then ground walnuts, beating to mix.
In a separate bowl, beat the egg whites until they are stiff (you can add a pinch of cream of tartar if necessary). Using a rubber spatula, fold into the egg whites into the walnut mixture.
Spread the mixture evenly in the prepared baking pan. Bake for about 15 minutes, or until a toothpick comes out clean.
Cover the cake with a damp cloth or dishtowel and place in the refrigerator for 30 minutes.
For the filling:
I usually wait about 10 or 15 minutes before beginning this step (while waiting, I generally hand wash some utensils; see Notes). If you haven’t done so in Step 4 above, grind 6½ ounces of walnuts.
Heat the milk until it's warm (the microwave works well for this), then add it to the ground walnuts. Set aside to cool.
In the mixing bowl of a stand mixer (or in a medium bowl if doing this by hand), cream the butter, gradually adding the sugar. Continue beating until the butter/sugar mixture is light and fluffy.
Beat in the Cognac and then the walnut/milk mixture.
In a separate bowl, beat the heavy cream until it becomes whipped cream.
Fold the whipped cream into the walnut mixture.
For final assembly:
Remove the cake from the refrigerator (make sure it’s been chilling for at least 30 minutes), and sprinkle the top of the cake with confectioners’ sugar.
Put a piece of waxed or parchment paper (at least 20 inches long) over the cake.
Keeping the waxed/parchment paper on top of the cake, grip the baking pan at both ends and quickly turn it 180 degrees (upside down).
Remove the pan, and peel the paper off the cake.
Using a spatula, spread the filling evenly over the top of the cake.
Roll the cake, using the remaining waxed paper to help roll it up into a jelly roll shape.
Cover the cake roll with foil, and refrigerate until firm (at least an hour or two).
Dust the top of the cake roll with confectioners’ sugar just before serving. Add additional garnish (such as mint or berries) if desired.