The Artesia Bakery is a Danish bakery which has the best birthday cake when they're "on" because of the frosting and a layer of custard in the middle. Not cheap, a quarter sheet cake costs just under $18, a whole sheet cake just under $40. The bakery also carries other Danish products from cookies to bread to pickles and bakes and decorates cakes to order.
Parking can be a problem. Try to go early in the day.