Place the thawed pound cake on a work surface. With sharp, long-bladed knife, trim dark top from cake to make cake level. With long-bladed knife, cut remaining cake horizontally into four equal layers, about 1/3 in ch thick.
with lond-bladed knife, cut remaining cake horizontally into four equal layers, about 1/3 inch thick.
Hazelnut Chocolate Frosting: In small saucepan, heat heavy cream just until bubbles appear around the edge of the pan. Remove the saucepan from the heat. Add chocolate; let stand1 minute. Stir until the chocolate is melted and the mixture is smooth.
Meanwhile, in a large bowl, beat together butter, confectioners' sugar, 3 tablespoons hazelnut liqueur and salt until blended. Beat in chocolate mixture until fluffy and smooth, about 5 to 8 minutes.
Place one cake layer ON BAKING SHEET; SPREAD WITH 2 TABLESPOONS FROSTING. PLACE A Cake layer on top; repeat with remaining frosting and cake layers, ending with a cake layer. ( Do not frost top of last layer).
With sharp, long-bladed knife, cut cake lengthwise and diagonally, starting at the long side on the upper right and cutting through the center of the cake to the long side on lower left.
Tip each cake so layers run vertically and each piece of cake sits on a long flat side with long sharp edge pointing up. Spread 2 tablespoons frosting onto one vertical wide side. Press two halves together to form cake triangle.
Brush diagonal cut edges of cake with remaining liqueur. Spread remaining frosting over sides and top of cake.Run cake comb on diagonal sides to create ridges.Refrigerate for 45 minutes for frosting to set.
Hazelnut Praline: Line a baking sheet with aluminum foil.Place the granulated sugar in a heavy 8-inch skillet; cook over medium heat, stirring occasionally, until the sugar is melted and amber in color, about 7 minutes. Add the hazelnuts. Quickly turn the sugar-hazelnut mixture out onto the prepared baking sheet, spreading evenly with a metal spatula.Let praline stand at room temperature until completely cool and brittle, Break the praline into pieces; coarsely chop the pieces.
Garnish: If desired, in a small bowl, beat chilled cream until moist, stiff peaks form, Spoon whipped cream into pastry bag fitted with decorative tip, and pipe at base of cake . Scatter Hazelnut Praline over top of cake ( save any extra for snacking.).
Note: To toast hazelnuts, spread on a baking sheet. Toast in 350 degree f oven until lightly colored and fragrant., 10 to 12 minutes.