SERVES 10 TO 12
Brandy and even whiskey can stand in for the dark rum. The test kitchen prefers a tiramisù with a pronounced rum flavor; for a less potent rum flavor, halve the amount of rum added to the coffee mixture in step 1. Do not allow the mascarpone to warm to room temperature before using it; it has a tendency to break if allowed to do so.
2½ |
cups strong brewed coffee, at room temperature |
9 |
tablespoons dark rum (see note) |
1½ |
tablespoons instant espresso powder |
6 |
large egg yolks, at room temperature |
⅔ |
cup (4⅔ ounces) sugar |
¼ |
teaspoon table salt |
1½ |
pounds mascarpone (generous 3 cups; see note) |
¾ |
cup heavy cream, chilled |
14 |
ounces (42 to 60, depending on size) dried ladyfingers |
3½ |
tablespoons cocoa powder, preferably Dutch-processed |
¼ |
cup grated semisweet or bittersweet chocolate (optional) |
1. Stir together the coffee, 5 tablespoons of the rum, and the espresso powder in a wide bowl or baking dish until the espresso dissolves; set aside.
2. In a stand mixer fitted with the whisk attachment, beat the egg yolks at low speed until just combined. Add the sugar and salt and beat at medium-high speed until pale yellow, 1½ to 2 minutes, scraping down the sides of the bowl with a rubber spatula once or twice. Add the remaining 4 tablespoons rum and beat at medium speed until just combined, 20 to 30 seconds; scrape the bowl. Add the mascarpone and beat at medium speed until no lumps remain, 30 to 45 seconds, scraping down the sides of the bowl once or twice. Transfer the mixture to a large bowl and set aside.
3. In the now-empty mixer bowl (no need to clean the bowl), beat the cream at medium speed until frothy, 1 to 1½ minutes. Increase the speed to high and continue to beat until the cream holds stiff peaks, 1 to 1½ minutes longer. Using a rubber spatula, fold one-third of the whipped cream into the mascarpone mixture to lighten, then gently fold in the remaining whipped cream until no white streaks remain. Set the mascarpone mixture aside.
4. Working one at a time, drop half of the ladyfingers into the coffee mixture, roll, remove, and transfer to a 13 by 9-inch glass or ceramic baking dish. (Do not submerge the ladyfingers in the coffee mixture; the entire process should take no longer than 2 to 3 seconds for each cookie.) Arrange the soaked cookies in a single layer in the baking dish, breaking or trimming the ladyfingers as needed to fit neatly into the dish.
5. Spread half of the mascarpone mixture over the ladyfingers; use a rubber spatula to spread the mixture to the sides and into the corners of the dish and smooth the surface. Place 2 tablespoons of the cocoa in a fine-mesh strainer and dust the cocoa over the mascarpone.
6. Repeat the dipping and arrangement of the ladyfingers; spread the remaining mascarpone mixture over the ladyfingers and dust with the remaining 1½ tablespoons cocoa. Wipe the edges of the dish with a dry paper towel. Cover with plastic wrap and refrigerate for 6 to 24 hours. Sprinkle with the grated chocolate (if using); cut into pieces and serve chilled.