Sacher Torte

FOR THE CHOCOLATE GENOISE: Adjust oven rack to middle position and heat oven to 350 degrees. Line bottom of 9-inch springform pan with circle of parchment paper.

Melt butter in small saucepan over low heat. Remove from heat and set aside. Sift flour, cocoa, and salt together onto large piece of parchment paper; set aside.

Whisk together eggs and sugar in bowl of standing mixer until combined. Place bowl over pan of barely simmering water, making sure that water does not touch bottom of bowl, and heat egg mixture, whisking constantly, until warm to touch, about 110 degrees. Remove from heat and beat at medium-high speed until eggs are pale, cream-colored, voluminous, and form thick ribbon of tiny billowy bubbles that falls from whisk and rests on top of batter for several seconds when whisk is held about 4 inches above egg mixture (this should take 6 to 8 minutes). Beat in vanilla. Turn off mixer, transfer 1 cup egg mixture to medium bowl, and stir in melted butter until combined; set aside.

Grab both ends of sheet of parchment paper holding flour mixture and fold in half; with mixer running at lowest speed, slowly sprinkle flour mixture into batter until just barely incorporated. Add melted butter mixture back to batter in standing mixer bowl and, with mixer still running at lowest speed, fold gently to incorporate, being careful not to deflate batter.

Immediately push batter from bowl into prepared springform pan with rubber spatula, holding bowl close to bottom of pan. Smooth top with offset spatula. Bake until cake is deep golden brown and springs back lightly when pressed with your finger, about 35 minutes. Transfer pan to wire rack and cool completely. When cake is cool, run blade of thin metal spatula around inside circumference of springform pan to loosen cake from sides of pan and remove. Invert cake onto plate or baking sheet, remove pan bottom and parchment paper, and reinvert cake onto rack.

FOR THE FILLING: Process apricot jam in food processor until smooth, about 10 seconds. Transfer to small saucepan and bring to simmer, stirring constantly, over medium heat. Remove from heat and cool to room temperature.

FOR THE GLAZE: Combine cream and corn syrup in medium saucepan and bring to full simmer over medium heat. Off heat, add chocolate; cover and let stand for 8 minutes. (If chocolate has not completely melted, return saucepan to low heat and stir constantly until melted.) Add vanilla; stir very gently until mixture is smooth. Cool until tepid so that spoonful drizzled back into pan mounds slightly.

TO ASSEMBLE THE TORTE: Using long serrated knife, cut 1 horizontal line around sides of fully cooled cake; then, following scored lines, cut cake into 2 even layers. Invert top layer of cake onto cardboard round cut just larger than diameter of cake. Using offset spatula, spread ½ cup of apricot jam evenly over cake. Invert second layer of cake over first. Place cake and cardboard round on wire rack that has been set on large rimmed baking sheet. Pour remaining apricot jam on top of cake and, using offset spatula, spread jam over edges and along sides of cake. Allow excess jam to fall off sides of cake onto baking sheet. Refrigerate cake on wire rack set on baking sheet until apricot jam is set, about 30 minutes.

Pour chocolate glaze on top of cake. Using offset spatula, spread glaze evenly over top of cake and spread it along sides of cake. Refrigerate cake, still on rack set over baking sheet, until set, at least 1 hour and up to 48 hours. Transfer cake to a large platter and serve.