Cook first 3 ingredients in a small saucepan over low heat, stirring constantly, until butter melts and mixture is smooth; remove butter mixture from heat.
Beat buttermilk, 2 eggs, baking soda, and vanilla at medium speed with an electric mixer until smooth. Add butter mixture to buttermilk mixture, beating until well blended.
Combine sugar, flour, and salt; gradually add to buttermilk mixture, beating until blended.
Coat 3 (9-inch) round cakepans with cooking spray, and line pans with wax paper. Pour cake batter evenly into pans.
Bake at 350° for 18 to 22 minutes or until cake is set. Cool in pans on wire racks 10 minutes. Remove from pans, and cool completely on wire racks.
Spread about 1/2 cup Chocolate Ganache between cake layers, and spread remaining ganache on sides of cake.
Pour Praline Frosting slowly over the center of cake, gently spreading to edges, allowing some frosting to run over sides. Freeze, if desired; thaw at room temperature 4 to 6 hours. Garnish, if desired.