I've been holding out on you. I know, I'm sorry. I don't even know why — because these lemon bars ... oh man, they are meant to be shared. In fact, keeping them to yourself would be very dangerous. The truth is that I've been making this lemon curd recipe on its own for years, and I've been tinkering with my favorite shortbread recipe for years. Now, finally, I've had the presence of mind to bring them together. No need to thank me — you're welcome.