until butter is melted, stirring occasionally. Pour into 2 8 or 9" round cake pans; sprinkle evenly with chopped pecans. In large bowl, combine cake mix, water, oil and eggs at low speed until moistened; beat 2 minutes at highest speed. Carefully, spoon batter over pecan mixture. Bake @ 325 degrees 35 to 45 minutes or until cake springs back when touched lightly in center. Cool 5 minutes. Remove from pans. Cool completely. In small bowl, beat 1 3/4 cups whipping cream until soft peaks form. Blend in powdered sugar and vanilla; beat until stiff peaks form. To assemble cake, place 1 layer on serving plate, praline side up. Spread with 1/2 of whipped cream. Top with second layer, praline side up; spread top with remaining whipping cream. Garnish with whole pecans and chocolate curls, if desired. Store in refrigerator.