I know this will be a very unpopular response, but I think "healthy dessert" is an oxymoron. With the exception of fresh fruit served with cheeses like they do in Europe, I don't think dessert is even supposed to be healthy. My philosophy is to eat a small or half portion of a great, satisfying dessert occasionally to avoid feeling deprived. I've found that when I'm really feeling deprived of foods that I'm craving, I tend to cheat in a huge way (like eat a dozen or so cookies or half a carton of ice cream). Does anybody else feel this way, or am I just nuts?
I do try to add healthy ingredients to my desserts when appropriate (like a little whole wheat flour, ground flax, or another healthy grain), but I've found cutting the fat in baked goods and substituting low-fat items just makes the final product tough or substandard; those types of desserts aren't really worth eating anyway.