There were a few challenges. New cake pan, of a size that doesn't quite match a classic Bundt pan or a 10" tube pan. Might be designed to be the capacity of a "standard" 2-layer cake. And then there's the niece's Type 1 diabetes, diagnosed just before Christmas. Oh, and the cake must be chocolate.
I found a 2-layer chocolate cake recipe for Splenda Blend (a mix of sugar and Splenda sweetener, designed for baking) on the Splenda Web site. My sister-in-law warned that the Splenda Blend recipes are very sweet, but I was afraid to cut back on the amount because sugar is pretty necessary for the structure of a cake--and then, the 10-year-olds who are going to eat it probably won't care anyway. We also decided not to add a glaze, both to avoid adding more carbohydrates and to not hide the detail on the cake.
So far, so good--the cake recipe made enough batter, even though I need to work on how to get it to fill in the front of the castle when it rises. I also didn't rap the pan hard enough, and had a couple of air bubbles in the turrets...will work on that next time, too. We have tall candles with a flag on them for each tower, and shorter ones for the ramparts to make up the numbers. Niece brought over her stash of sugar-free candies and gum and we stuck various pieces on the windows, with gum "planks" on the drawbridge. Ganache makes a nice glue.
I'll take pictures of the completed cake at the party tomorrow. I just wish I had a tabletop grape trebuchet to complete the presentation, like celticdragonfly and selenite!