A rich Dobos Torte -- which has alternating layers of yellow genoise cake and Caramel Buttercream -- is topped with coarsely chopped caramelized sugar. The original recipe was created in 1887 by the Hungarian chef whose name it bears.
Preheat oven to 350 degrees, with rack in center. Butter two 12-by-17-inch rimmed baking sheets. Line bottoms with parchment paper; butter parchment, and sprinkle with flour, tapping out excess. Set aside.
In the heatproof bowl of an electric mixer set over a pan of simmering water, whisk together sugar, eggs, and salt until mixture is warm to the touch and sugar has dissolved, about 2 minutes.
Attach bowl to mixer fitted with the whisk attachment, and beat egg mixture on high speed until very thick and pale, 6 to 8 minutes. Gently transfer mixture to a large shallow bowl.
Sift in two-thirds of the flour in two batches, folding gently after each addition. In a small bowl, combine melted butter and extracts, and add to egg mixture in a steady stream as you sift in the remaining flour; fold gently, and divide batter between prepared baking sheets, smoothing tops with an offset spatula.
Bake until cakes are springy to the touch and lightly golden brown, 10 to 12 minutes. Transfer to a wire rack to cool completely before inverting cakes onto rack, and remove parchment paper. Cut each cake into three 5 1/4-by-11 1/4-inch rectangles (you will use only five; reserve the remaining piece for another use).
Lay one rectangle on a flat work surface. Using a pastry brush, soak with a little less than 1/4 cup simple syrup. Using an offset spatula, spread 1 cup buttercream evenly over the top. Place another rectangle on top, and continue until you have five cake layers soaked with syrup and topped with buttercream. Spread remaining buttercream over sides of cake, and smooth the top and sides to form a neat block.
Refrigerate until firm, at least 30 minutes. When ready to serve, sprinkle chopped caramel over the top.