Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking pan. Pour boiling water over dates in a small bowl, and let stand until cool.
Measure flour, baking powder, soda, salt, and nuts into a small bowl. Stir to mix.
Cream 1/4 cup butter and white sugar together in a mixing bowl; beat in egg and vanilla. Add flour mixture to creamed mixture in three parts alternately with date mixture in two parts, beginning and ending with dry mixture. Spread cake batter into prepared pan.
Bake in the preheated oven until an inserted wooden pick comes out clean, 30 t0 40 minutes.
To make the topping: Mix coconut, brown sugar, 6 tablespoons butter and cream in a small saucepan over medium heat. Boil for three minutes. Spread over warm cake, and brown under broiler.
