Our recipe for this is in Mamcik’s handwriting, in faded blue ink on a folded piece of yellowing paper. Like so many of our family recipes, it is more “notes to remind you how to do it” rather than exact instruction. For example, it doesn’t say a word about how to construct and assemble this famous dessert, so we’ve added that. It also doesn’t include instructions for the final chocolate glaze, so we’ve swiped that from the Hotel Sacher’s online recipe. There also is a version on King Arthur Baking’s site that looks very much like the original.

• 1 stick butter
• 1 cup dark chocolate, melted
• 1 teaspoon vanilla (optional: scrape the seeds from 1/4 vanilla bean)
• Pinch salt
• 3 tablespoons milk
• 6 eggs, separated
• 1 cup sugar
• 1 cup cake flour
• 1/2 to 1 cup apricot marmalade or jam*
• 1 cup dark chocolate, melted
• 1/2 cup water
• 1 cup sugar

Preheat oven to 350 degrees. Butter two 9-inch round cake pans well, and line with parchment. It’s wise to butter the parchment lightly as well.

Melt the butter and chocolate separately. In a small bowl, lightly beat the egg yolks. Add the melted chocolate, melted butter, vanilla, salt, and milk. Blend until smooth.

In a stand mixer, beat egg whites on medium until foamy; then slowly add sugar. Switch to high speed, and beat until glossy with stiff peaks. Fold about a quarter of the whites into the chocolate mixture and mix. Now add the chocolate to the remaining egg whites in the stand mixer bowl. Fold gently. Sprinkle the cake flour over the mix and continue to fold gently until you no longer see lumps of egg white. (This is tricky to do without getting impatient and deciding just to stir it aggressively, but if you do that you will knock all the air out of the batter and ruin the cake.)

Pour the batter into the pans, and bake with the oven door ajar for about 10-15 minutes. Close the oven door and continue to bake for about 45 minutes, or until it springs back when you pat the surface with a finger. If you use the toothpick test, the center should come out clean.

Cool on a wire rack for 10-20 minutes. Then turn the cakes out onto the wire rack, remove the parchment paper, and allow to cool completely.

When the cakes have cooled, spread the apricot marmalade on top of both layers, and stack them. You can add more to the sides of the cake or leave the sides dry; it’s done both ways. Spread fresh parchment paper underneath the wire rack.

To make the final glaze, put the water into a small saucepan over medium-high and add the sugar. Heat until the syrup boils, the sugar melts, and boil for about 5 minutes. Remove from heat. Chop the remaining 1 cup of dark chocolate (if you haven’t already), and gradually mix it into the syrup. Stir until it thickens.

Immediately pour the glaze over the layered cake. Use a spatula to smooth the top, and gently cover the sides of the cake. You can scrape up the drips from the parchment paper and spread them over any bare spots.

Before serving, allow glaze to cool and set, but don’t put it into the refrigerator or the glaze will turn dull and sticky.

Enjoy, and have seconds, because this cake won’t hold for more than a day.

*Carla hates apricot; she will only order this cake at a restaurant when they tweak the recipe and serve it with raspberry jam. It is delicious. So feel free to experiment.