Preheat oven to 325 degrees.
In small heavy saucepan, combine butter, 1/4 c whipping cream, and brown sugar.
Cook over low heat just until butter is melted, stirring occasionally.
Pour into two 8 or 9 inch round pans.
Sprinkle evenly with chopped pecans.
In large bowl, combine cake mix, water, oil, and eggs.
Beat at low speed until moistened.
Beat 2 minutes at medium speed.
Carefully spoon batter over pecan mixture.
Bake 35 - 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 c whipping cream until soft peaks form.
Add powdered sugar and vanilla.
Beat until stiff peaks form.
To assemble cake, place 1 layer on serving plate, praline side up.
Spread with half of whipped cream.
Top with second layer, praline side up.
Spread top with remaining whipped cream.
Store in refrigerator.