In a large mixing bowl, combine dates, the boiling water, the butter or margarine and the baking soda. Let mixture stand until cool.
Add flour, granulated sugar, and egg. Beat with an electric mixer on low to medium until combined. Stir in the nuts. Pour the batter into a greased and floured 13x9x2-inch baking pan.
Bake in a 350 degree F oven for 20 to 25 minutes or until cake springs back when you touch it. Cool in pan on wire rack.
Prepare and cool sauce.
In a chilled bowl, combine cream and vanilla. Beat with chilled beaters of an electric mixer on medium speed until soft peaks form (tips curl).
Tear cake into bite-size pieces. In a 2-quart serving bowl, layer half of the pieces of the cake. Top with half of the sauce and half of the whipped cream. Repeat the layers. Serve the layered pudding immediately.
In a medium saucepan, combine packed brown sugar, 1 cup water, and butter. Bring to boiling. Stir together cornstarch and 1 cup water. Add to brown sugar mixture in saucepan. Cook and stir until thickened and bubbly. Cook and stir for 2 minutes more. Remove from heat. Stir in vanilla. Cover surface with plastic wrap. Cool completely.