For Cake: Preheat oven to 350 degrees F. Grease two 8- to 9-inch round cake pans. Using electric mixer, cream butter and brown sugar. Beat in eggs in thin stream. Combine flour, baking powder and baking soda in another bowl. Alternate adding dry ingredients, syrup and hot water to butter mixture, blending until smooth. Bake until tester inserted in center comes out clean, about 30 minutes. Cool completely. Wrap; chill thoroughly.

For Praline: Lightly grease baking sheet. Boil syrup in heavy small saucepan until candy thermometer registers 300 degrees F (hard-crack stage). Remove from heat. Stir in walnuts. Pour onto prepared sheet. Cool until set. Transfer to processor and mix to fine powder.

For Whipped Cream: Beat cream with sugar and extract to stiff peaks.

To Assemble: Cut off top crusts from cake layers. Set 1 layer on platter. Spread lightly with whipped cream. Sprinkle lightly with praline. Top with second cake layer. Spread top and sides lightly with whipped cream. Spoon remaining whipped cream into pastry bag fitted with star tip. Pipe lattice design atop cake; pipe border around bottom edge of cake. Press praline onto sides; sprinkle any remainder on top. Serve Maple Walnut Cake chilled or at room temperature.