You only have a birthday once a year and if you're going to eat cake you may as well enjoy eating cake instead of trying to convince yourself that a second rate excuse is just as good as the real thing
I thought this too.

I had a think, and two *relatively* low sugar desserts you could make (which have dark chocolate) would be profiteroles or tiramisu. Otherwise, the chocolate cake I make, has 1 1/2 cups of white sugar, which is a bit, but it makes a fairly big cake, with 2 1/2 cups of flour. I can post the recipe if you like.