Although often mistaken for a pastry, this small, delicate dessert is actually miniature cake. Light and moist, it is very similar in many ways to sponge cake. The cakes were invented in the late 1800s by a pastry chef in Paris known as Lasne. His bakery was near the Paris Stock Exchange and this inspired two major features of his cake: He created the texture so that when it was eaten out of hand, it would not discolor or leave residue (quite welcome to all of the office workers in the financial district). The other feature: Lasne created a pan for the cakes similar in shape to a gold bar, another fitting aspect for his clientele. Like many of the dry sweets of the eighteenth century, financiers : a cross between little cakes and cookies. Usually prepared with almonds, this recipe is varied to use flour made from pistachios, which Thomas Jefferson cultivated at Monticello for some years.