A traditional Italian tiramisu calls for ladyfingers soaked in or brushed with a mixture of espresso and coffee-flavored liqueur. The soaked cookies are layered with a whipped mascarpone sweet cream, like a trifle. The dessert sets for at least two hours, though many recipes call for at least 24 hours in the refrigerator before serving. The setting time allows the coffee flavor to penetrate the ladyfingers, rendering the cookies soft and moist. If you are swapping out the ladyfingers for margherite cookies, replicating the texture of soaked ladyfingers is the most challenging aspect of the substitution.

Margherite cookies are an appropriate substitute for ladyfingers for several reasons. Like ladyfingers, margherite cookies are slightly sweet with a hint of vanilla. They are also similarly shaped and sized: short, thin and just slightly rounded. If you have difficultly finding ladyfingers, you'll probably have more luck finding margherite cookies, which are available in most grocery stores in the cookie and cracker aisle.

American versions of ladyfingers are soft, with a texture similar to pound, sponge or angel food cake. Margherite cookies are closer in texture to shortbread; they are firmer and more like a cookie than a cake. In tiramisu, margherite cookies give the dessert a heavier texture because they lack the airiness of ladyfingers. However, traditional Italian ladyfingers are dryer than American versions; some recipes even call for toasting American style ladyfingers to get them closer to the original version. If you are used to traditional Italian tiramisu, the texture difference will be less pronounced should you use magherite cookies.

If you are using margherite cookies, place the cookies in a small plastic container and pour the liquid mixture over them rather than brushing it on. Let the cookies absorb the moisture for several minutes before layering the dessert. Allowing the tiramisu to set in the refrigerator for as long as possible allows the cookies to soften; at least 12 and up to 24 hours softens the cookies to simulate the ladyfinger texture.