I used to help my mom assemble the cake, but never made the whole thing myself except for the >>>
Honeycomb brittle. This pretty easy. Be sure to use a tea strainer to sift the baking soda into the hot syrup so it disperses evenly, otherwise you may have clumps of baking soda-yuck!. It will bubble up vigorously and quite high so use a high-sided pan (I use the bottom of a pressure cooker.) Pour the candy out on a foil lined pan. When it cools completely it will come off and break up nicely.
My Mom used plain whipped cream and added toasted sliced almonds as well as the brittle to the outside. My sisters and I don't remember whether the brittle was in between the layers as it melts when assembled too far ahead. I plan to bake the spongecake in a tube pan with a removeable bottom and slice into 3 or 4 layers. We will assemble at the last minute.
