It's the only one that will do, and it has a history.
My mother tended to take a rather practical approach to cooking; with four kids to feed every night she didn't always have a lot of time for experimentation or trying out new recipes. But there were some things that she did really well, and my birthday cake was one of them.
In the beginning she just bought a lemon cake (even as a kid I loved citrusy flavors) from a bakery. Then she decided to try making one herself, and eventually she got pretty good at it. My favorite part was always the crusty outside, and because it was my birthday I got to cut the outside off and have it all to myself.
Once I started making the now-famous (well, in my family, anyway) lemon cake, I wanted to change it up a bit, make the cake itself more tender and lemony, and add some excitement to it. I mixed some candied lemon peel into the batter, and then topped the cake with a fudgy glaze, since I'm such a chocolate lover. That combo—chocolate and lemon—is still one I can't resist.
It's just not my birthday without this cake. When it's baking, the whole house smells like memories!