This is a Cinderella dessert story. From simple leftovers—some coffee, leftover cake or cookies, an enrichment of cream or mascarpone—a prince of a dessert is born. Tiramisù is an Italian creation, but its popularity in American began in San Francisco and today is as beloved in the United States as it is in Italy. It can be made in advance, keeps well, is great to serve big numbers, and can even be frozen and remain delicious.
1 pound bittersweet chocolate, chopped
2 cups heavy cream
2 cups mascarpone, at room temperature
1 cup confectioners’ sugar
2 cups freshly brewed espresso
½ cup granulated sugar
½ cup coffee liqueur
48 savoiardi cookies (ladyfingers)
Melt the chocolate in a double boiler over simmering water, and keep it warm in the double boiler.
Meanwhile, whisk the cream in an electric mixer fitted with the whisk attachment until it just holds soft peaks. (Don’t overwhip, because you will be whisking it again with the mascarpone, and you don’t want to make butter!)
Whisk the mascarpone in a separate bowl with the mixer on medium speed until smooth. Sift in the confectioners’ sugar and whisk until smooth. Whisk the whipped cream into the mascarpone until they are just combined. Refrigerate if not using right away.
Combine the espresso and granulated sugar in a medium saucepan set over low heat. Cook until the sugar has dissolved, then stir in the coffee liqueur. Remove from heat, and stir in about two-thirds of the melted chocolate. Pour the chocolate-espresso mixture into a large shallow pan, big enough to soak half the savoiardi at one time. Add half of the savoiardi to soak the liquid, and soak, turning to coat all sides until almost soaked through, about 1 minute.
Arrange the savoiardi in two rows in the bottom of a 9-by-13-inch (3-quart) Pyrex dish or ceramic dish to make a tight bottom layer, breaking as necessary to patch empty spaces. Drizzle with a third of the remaining warm melted chocolate. Spread half of the mascarpone in an even layer over the top of the cookies.
Soak the remaining twenty-four savoiardi in the remaining soaking liquid. (You should have used up most of the soaking liquid by this point.) Arrange the soaked savoiardi on top of the mascarpone, just as you did the first layer, and drizzle with another third of the warm melted chocolate.
Spread the remaining mascarpone in an even layer over top. Pour the remaining melted chocolate on top. Use a toothpick or paring knife to make lines at 2-inch intervals connecting the long sides of the pan. Now make perpendicular lines through the chocolate to create a crosshatch pattern. Chill the tiramisù at least 4 hours or up to overnight before cutting into squares to serve.